5,492 research outputs found
Application of Raman and Brillouin Scattering Phenomena in Distributed Optical Fiber Sensing
We present a review of the basic operating principles and measurement schemes of standalone and hybrid distributed optical fiber sensors based on Raman and Brillouin scattering phenomena. Such sensors have been attracting a great deal of attention due to the wide industrial applications they offer, ranging from energy to oil and gas, transportation and structural health monitoring. In distributed sensors, the optical fiber itself acts as a sensing element providing unique measurement capabilities in terms of sensing distance, spatial resolution and number of sensing points. The most common configuration exploits optical time domain reflectometry, in which optical pulses are sent along the sensing fiber and the backscattered light is detected and processed to extract physical parameters affecting its intensity, frequency, phase, polarization or spectral content. Raman and Brillouin scattering effects allow the distributed measurement of temperature and strain over tens of kilometers with meter-scale spatial resolution. The measurement is immune to electromagnetic interference, suitable for harsh environments and highly attractive whenever large industrial plants and infrastructures have to be continuously monitored to prevent critical events such as leakages in pipelines, fire in tunnels as well as structural problems in large infrastructures like bridges and rail tracks. We discuss the basic sensing mechanisms based on Raman and Brillouin scattering effects used in distributed measurements, followed by configurations commonly used in optical fiber sensors. Hybrid configurations which combine Raman and Brillouin-based sensing for simultaneous strain and temperature measurements over the same fiber using shared resources will also be addressed. We will also discuss advanced techniques based on pulse coding used to overcome the tradeoff between sensing distance and spatial resolution affecting both types of sensors, thereby allowing measurements over tens of kilometers with meter-scale spatial resolution, and address recent advances in measurement schemes employing the two scattering phenomena
Planning the Integrated Management of Organic Waste Flows and Agricultural Residues for a Circular Economy
In the recent years, the production, management and disposal of both organic waste and agricultural residues has become significantly difficult in Italy, due to the lack of suitable facilities. Very often, indeed, within the different regions, there are no treatment plants for the organic fraction of municipal solid waste or agricultural residues treatment centres, so as to give them a second life in the perspective of a circular economy. The lack of proximity treatment centres, forces local administrations to send these flows to plants outside their territorial area, with a consequent
increase for transport and treatment costs. This paper, with reference to the study area of the Matera municipality (Basilicata region - Southern Italy), taking into consideration the organic waste flows of non-domestic users from separate collection and agricultural residues - especially those coming from the wine production chain - provides a state-of-the-art analysis of the problems related to their collection, management and disposal. Subsequently, an alternative model feasibility study - called "proximity composting", aimed at a more sustainable management of these flows based on their “zero-kilometers treatment” – has been implemented. The results obtained have demonstrated that the proposed scenario is much more sustainable when compared to the
current situation, both from an economic and environmental point of view. Indeed, thanks to the use of calculation tools, the economic (€/year) and environmental (Kg CO2 avoided/year) advantages, due to the save of transport and disposal of flows outside the region, have been quantified, with consequent reduction of waste tax for citizens (€/year). In addition, the implementation of maps using a Geographical Information System (GIS) has demonstrated a better optimization of the system. Finally, it was highlighted the social utility of the proposed model, because citizens become an active part in the process and self-produce soil fertilisers
Entanglement entropy and quantum field theory: a non-technical introduction
In these proceedings we give a pedagogical and non-technical introduction to
the Quantum Field Theory approach to entanglement entropy. Particular attention
is devoted to the one space dimensional case, with a linear dispersion
relation, that, at a quantum critical point, can be effectively described by a
two-dimensional Conformal Field Theory.Comment: 10 Pages, 2 figures. Talk given at the conference "Entanglement in
Physical and information sciences", Centro Ennio de Giorgi, Pisa, December
200
Experimental analysis on concrete blocks reinforced with Arundo donax fibres
Over the last decades, there has been growing attention in research and development on non-conventional building materials, such as vegetable fibres (e.g., flax, hemp, jute, etc.), to be used
as eco-friendly materials in a wide range of applications in civil construction. The main reasons for this interest are related to the specific properties, price, and sustainability of natural fibres,
which can be considered ‘green’ building materials. In this article, the tensile strength of a new type of fibre extracted from the stem of the Giant Reed Arundo donax L. has been investigated. First, these fibres, which widely grow in Mediterranean areas but are diffused worldwide as well have been extracted from the outer part of the plant stem. Then, in order to have an initial idea of their influence on the mechanical properties of concrete, some experimental bricks have been prepared, with the addition of different weight percentages of this vegetal fibre. Compression and tensile tests on the whole block have been performed to assess the mechanical properties of these bricks. Hence, the differences between concrete bricks without fibre and those reinforced with different weight percentages of natural fibre have been analysed, assessing their potential applications in bio-architecture
Experimental analysis on concrete blocks reinforced with Arundo Donax fibers.
Over the last decade, there has been a growing attention in research and development on non-conventional building materials and technologies, such as vegetable fibers (e.g., flax; hemp; jute; etc.), to be used as eco-friendly materials in a wide range of applications in civil construction. The main reasons of this interest are related to the specific properties, price and sustainability of natural fibers, which can be considered as “green” building materials. In this article, a new kind of fibers, extracted from stem of the Giant Reed Arundo donax L., has been investigated as a potential reinforcement of construction materials. These fibers, which widely grow in Mediterranean areas, but that are diffused all around the world as well, have been extracted from the outer part of plant stem. Then, some experimental concrete bricks, have been prepared with the addition of different weight percentages of vegetal fiber. To assess the mechanical properties of these bricks, tensile tests on single fiber have been performed, as well as compression tests on the whole block. Hence, the differences between concrete bricks without any fiber and those reinforced with different weight percentages of natural fiber have been analyzed, and their potential applications in bio-architecture have been assessed
Concrete Blocks Reinforced with Arundo donax Natural Fibers with Different Aspect Ratios for Application in Bioarchitecture
In recent decades, the construction industry has advanced in its use of natural green resources, such as vegetable fibers (e.g., flax, hemp, jute, etc.) added in concrete mixtures, to create
building materials that are both economically and environmentally sustainable. The pricing, low energy cost, and environmental sustainability of these natural fibers are driving this interest. The
quantity of fibers and the ratio of fiber length to its transverse diameter (aspect ratio) are critical characteristics that have a decisive impact on concrete’s mechanical qualities. The influence of the aspect ratio of Arundo donax fibers on the tensile characteristics of concrete blocks was specifically investigated in this study. These fibers were collected from the outer section of the stem of this plant, which grows commonly in Mediterranean locations, but that is also found all over the world. Experiments were carried out on cylindrical concrete blocks with a constant amount of fiber (1 percent by weight) and different aspect ratios: 30, 50, and 70 (mm/mm) respectively, to assess their tensile strength, even when compared with concrete blocks without any fiber addition. Tensile tests on Arundo donax fibers were also conducted, with the aim to contribute to the analysis of their interaction with cementitious matrices, and to assess differences between the various compositions. The results showed a direct impact of the aspect ratio on the final tensile strength of concrete blocks, with higher aspect ratios producing superior tensile properties
GIScience and Historical Cartography for Evaluating Land Use Changes and Resulting Effects on Carbon Balance
Multi-chronological examination of territory using GIScience and historical cartography may reveal a strategic tool for investigating changes in land use and the surrounding landscape
structure. In this framework, the soil plays a key role in ecosystem evolution, since it governs all the mechanisms at the basis of vegetal growth, as well as all components of the total environment contributing to the formation of a rural landscape, including the balance of carbon dioxide. The present study was developed using a GIS approach applied to historical maps and aims to assess the environmental impact of land-use change, with particular attention to its effects on agricultural soil and atmospheric carbon dioxide balance. Thanks to a comparison between historical cartographic maps of different periods, this geospatial approach has enabled the assessment of the evolution of the rural land of the study area in the municipality of Ruoti (Basilicata Region—Southern Italy). This area, indeed, has been affected by deep land-use transformations, mainly caused by agricultural activities, with a resulting impact on the atmospheric CO2 balance. These transformations have been analyzed and quantified in order to contribute to the understanding on how the changes in land use for agricultural purposes have led to unforeseen changes in the rural landscape, ecosystems and the environment. The results showed that the greatest changes in land use were caused by the abandonment of large rural areas, resulting in the expansion of urban areas, a decrease in orchard and arable land (about less 25%), and an increase in woodland (more than 30%). These changes have resulted in a doubling in soil carbon fixation value. The final results have therefore confirmed that historical cartography within a GIS approach may decisively offer information useful for more sustainable agricultural activities, so as to reduce their negative contribution to climate change
Junctions of anyonic Luttinger wires
We present an extended study of anyonic Luttinger liquids wires jointing at a
single point. The model on the full line is solved with bosonization and the
junction of an arbitrary number of wires is treated imposing boundary
conditions that preserve exact solvability in the bosonic language. This allows
to reach, in the low momentum regime, some of the critical fixed points found
with the electronic boundary conditions. The stability of all the fixed points
is discussed.Comment: 16 pages, 2 figures, typos corrected, Refs adde
[Abolishing mandatory routine medical and laboratory examination of food handlers may have influenced the reporting trends of foodborne diseases? Frequency of notified foodborne illnesses in Southern Italy from 1996 to 2009]
The aim of this study is to compare notifications of foodborne diseases in Southern Italy, before and after abolishing mandatory medical and laboratory examination routine. Data were obtained from the National Epidemiological Report of Health Ministry, that includes the annual summaries of foodborne infectious illnesses notified in Italy. The average number of foodborne diseases per million inhabitants per year decreased after the abolishment of health card for all examined conditions. There was a statistically significant reduction in all Regions for Salmonellosis and in Basilicata, Calabria, Campania and Sicily for Brucellosis. Abolishing health card of food handlers workers did not increase trends of foodborne illnesses and foodborne epidemics in Southern Italy. Examined data confirm the substantial effectiveness of food handlers self-control and training as essentials instruments of Evidence Based Prevention
IGF-I influences everolimus activity in medullary thyroid carcinoma
Context: Medullary thyroid carcinoma (MTC) is a rare tumor originating from thyroid parafollicular C cells. It has been previously demonstrated that insulin-like growth factor I (IGF-I) protects MTC from the effects of antiproliferative drugs. Everolimus, an mTOR inhibitor, has shown potent antiproliferative effects in a human MTC cell line, TT, and in two human MTC primary cultures.
Objective: To verify whether IGF-I may influence the effects of everolimus in a group of human MTC primary cultures.
Design: We collected 18 MTCs that were dispersed in primary cultures, treated without or with 10 nM-1 mu M everolimus and/or 50 nM IGF-I. Cell viability was evaluated after 48 h, and calcitonin (CT) secretion was assessed after a 6 h incubation. IGF-I receptor downstream signaling protein expression profile was also investigated.
Results: Everolimus significantly reduced cell viability in eight MTC [by similar to 20%; P < 0.01 vs. control; everolimus-responders (E-R) MTCs], while cell viability did not change in 10 MTCs [everolimus-non-responders (E-NR) MTCs]. In E-R MTCs, IGF-I blocked the antiproliferative effects of everolimus that did not affect CT secretion, but blocked the stimulatory effects of IGF-I on this parameter. IGF-I receptor downstream signaling proteins were expressed at higher levels in E-NR MTC as compared to E-R MTCs.
Conclusion: IGF-I protects a subset of MTC primary cultures from the antiproliferative effects of everolimus and stimulates CT secretion by an mTOR mediated pathway that, in turn, may represent a therapeutic target in the treatment of aggressive MTCs
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