1,721,369 research outputs found
Micro-arthropod communities under human disturbance: is taxonomic aggregation a valuable tool for detecting multivariate change? Evidence from Mediterranean soil oribatid coenoses
No full textAnimal communities are sensitive to environmental disturbance, and several multivariate methods have recently been developed to detect changes in community structure. The complex taxonomy of soil invertebrates constrains the use of the community level in monitoring environmental changes, since species identification requires expertise and time. However, recent literature data on marine communities indicate that little multivariate information is lost in the taxonomic aggregation of species data to high rank taxa. In the present paper, this hypothesis was tested on two oribatid mite (Oribatida, Acari) assemblages under two different kinds of disturbance: metal pollution and fires. Results indicate that data sets built at the genus and family systematic rank can detect the effects of disturbance with little loss of information. This is an encouraging result in view of the use of the community level as a preliminary tool for describing patterns of human-disturbed soil ecosystems
Thermoelectric Generators (TEG) for the Powering of Energy-Hungry LoRaWAN-Based Sensor Nodes in Industrial Applications
No full textThe purpose of this study is to demonstrate the practical application of thermoelectric generators (TEGs) in low-power, energy-hungry wireless sensor systems, with the aim of providing complete energy self-sufficiency to these devices. To this end, an energy-hungry particulate matter (PM) sensor was integrated into a Long-Range Wide Area Network (LoRaWAN)based sensor node, and tested to evaluate the efficacy of the energy harvesting solution. Energy management was facilitated through the use of a low voltage power management integrated circuit (IC), which regulated both the power extraction from the TEGs and the charging process of a Li-Ion battery that powered the whole system. The architecture of the low-power wireless sensing system, integrating an energy-hungry PM sensor is presented, along with a theoretical analysis of its power consumption and the energy requirements for the implementation of effective energy harvesting using TEGs. The final objective of the work is the optimization of the sensor node life time, balancing the frequency of the achievable sensors samplings and data transmissions with the temperature gradient between the TEG faces. The low voltage power manager IC plays a crucial role in ensuring efficient power extraction and regulation, thereby contributing to optimal performance of the system
A new formulation of the geometric series with applications to oribatid (Acari, Oribatida) species assemblages from human-disturbed Mediterranean areas
No full textThe mathematical properties of the geometric series are revisited and the model is applied to oribatid mite (Acari, Oribatida) assemblages from Mediterranean areas that have been disturbed by human activity. In the past, the geometric series has been considered an ideal form of Fisher’s log model. However, in some cases data fit both models or the geometric series offers a better fit. Data presented in this paper and collected from areas heavily disturbed by human activity show that the species abundance distribution of oribatids is in almost all cases well fitted by the geometric series, indicating a common trend in the response to disturbance of this assemblage. The proposed new version of the model allows interesting applications in environmental monitoring because it is easy to outline the quantitative relationship between the abundance of the most abundant species, the total number of individuals and the total number of species in the sample
Piezoelectric Sensors as Energy Harvesters for Ultra Low-Power IoT Applications
Full text linkThe aim of this paper is to discuss the usability of vibrations as energy sources, for the implementation of energy self-sufficient wireless sensing platforms within the Industrial Internet of Things (IIoT) framework. In this context, this paper proposes to equip vibrating assets like machinery with piezoelectric sensors, used to set up energy self-sufficient sensing platforms for hard-to-reach positions. Preliminary measurements as well as extended laboratory tests are proposed to understand the behavior of commercial piezoelectric sensors when employed as energy harvesters. First, a general architecture for a vibration-powered LoRaWAN-based sensor node is proposed. Final tests are then performed to identify an ideal trade-off between sensor sampling rates and energy availability. The target is to ensure continuous operation of the device while guaranteeing a charging trend of the storage component connected to the system. In this context, an Ultra-Low-Power Energy-Harvesting Integrated Circuit plays a crucial role by ensuring the correct regulation of the output with very high efficiency
Comparative analysis of two edaphic zoocenoses (Acari Oribatida; Hexapoda Collembola) in the area of Orio al Serio Airport (Bergamo, northern Italy)
No full textSpecies richness, abundance and diversity of oribatid mites and springtails in soil and litter were investigated at four sites in the area of Orio al Serio Airport (Bergamo, Italy). A total of 60 oribatid mite and 35 springtail species were collected from the sites. The general low diversity and evenness along with high dominance may be related to the sensitivity of these edaphic zoocoenoses to soil impoverishment which has been occurring in this part of the Italian pre-Alps for many years. Quantitative and qualitative differences were found among the investigated areas. Results show that less frequently disturbed soils are capable of restoring oribatid and springtail populations, leading to greater equilibrium. Results show that less frequently disturbed soils allow the restoration of more equilibrated oribatid and springtail populations. Species were divided into 8 autoecological and 11 chorological categories. Correspondence Analysis arranged these categories among the sites, confirming the above-mentioned trend.Species richness, abundance and diversity of oribatid mites and springtails in soil litter were investigated at four sites in the area of Orio al Serio Airport (Bergamo, Italy). A total of 60 oribatid mite and 35 springtail species were collected from the sites. The general low diversity and eveness along with high dominance may be related to the sensitivity of these edaphic zoocenoses to soil impoverishment which has been occurring in this part of the italian pre-Alps for many years.Quantitative and qualitative differences were found among the investigated areas. Results show that less frequently disturbed soils are capable of restoring oribatid and springtail population, leading to greater equilibrium. Results show that less frequently disturbed soils allow the restoration of more equilibrated oribatid and springtail populations. Species were divided into 8 autoecological and 11 chorological categories, Correspondance Analysis arranged these categories among the sites, confirming the above-mentioned trend
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