377 research outputs found
Sea wave energy. A review of the current technologies and perspectives
The proposal of new technologies capable of producing electrical energy from renewable sources has driven research into seas and oceans. Research finds this field very promising in the future of renewable energies, especially in areas where there are specific climatic and morphological characteristics to exploit large amounts of energy from the sea. In general, this kind of energy is referred to as six energy resources: waves, tidal range, tidal current, ocean current, ocean thermal energy conversion, and saline gradient. This review has the aim to list several wave-energy converter power plants and to analyze their years of operation. In this way, a focus is created to understand how many wave-energy converter plants work on average and whether it is indeed an established technology
A review of the water desalination technologies
Desalination is commonly adopted nowadays to overcome the freshwater scarcity in some areas of the world if brackish water or salt water is available. Different kinds of technologies have been proposed in the last century. In this paper, the state of the mainstream solutions is reported, showing the current commercial technologies like reverse osmosis (RO), Multi-Stages Flash desalination (MSF) and Multi-Effect Distillation (MED), and the new frontiers of the research with the aim of exploiting renewable sources such as wind, solar and biomass energy. In these cases, seawater treatment plants are the same as traditional ones, with the only difference being that they use a renewable energy source. Thus, classifications are firstly introduced, considering the working principles, the main energy input required for the treatment, and the potential for coupling with renewable energy sources. Each technology is described in detail, showing how the process works and reporting some data on the state of development. Finally, a statistical analysis is given concerning the spread of the various technologies across the world and which of them are most exploited. In this section, an important energy and exergy analysis is also addressed to quantify energy losses
Investigation on a bio-composite material as acoustic absorber and thermal insulation
In order to limit the anthropic emissions of CO2, research is currently investigating new materials for the building sector. The main purpose is the reduction in the embodied energy consumption, especially in the residential sector, and consequently the limitation of the direct and indirect utilization of fossil fuels, for the indoor heating, cooling, and ventilation services. Indeed, the residential sector is affected by a high energy demand, thus the choice of improved materials is fundamental to improve the sustainability. All phases: construction, building life, and dismantling are impacting in terms of resource and energy consumption, both associated with the emissions of pollutants in the atmosphere. The aim of this experimental research is to study the thermal insulation and the acoustic absorption of a material composed by natural lime, water, and shives from sativa hemp, a variety of hemp usable for industrial applications. In order to assess the main characteristics of this material, some specimens have been made according to required shapes and sizes to test them in specific machines. The results obtained from the tests are compared with the values of similar lime-based materials already available on the market. The comparison shows how, in certain aspects, the lime and hemp shives materials represent a concrete alternative to conventional materials. This completely natural material would like to achieve thermal and acoustic comfort in indoor environments
FEM Analysis: A Review of the Most Common Thermal Bridges and Their Mitigation
The necessity to improve the energy saving potential of buildings is now a duty. European and national policies are being implemented to address the important decisions being made on this subject. For these reasons, several studies focus on this relevant topic. This paper review not only focusses on it but studies it in-depth. A commercial 3D simulation software was used to design a building sited in Palermo estimating the thermal losses before and after external envelope insulation. In particular, all the thermal bridges (TBs) were analysed with the finite element method (FEM) and mitigated with rock wool insulation. The paper shows the linear thermal transmittance difference and heat flux loss before and after TB mitigation. The results confirm the importance of installing an external insulation layer in the old building envelope. The linear thermal transmittance of TBs and the associated heat flux loss often decrease by more than 50%
Energy Efficiency in Historic Architecture: The “Ex Institute of Zoology and Comparative Anatomy” in Palermo
In Italy, a large part of the buildings classified as historical-artistic heritage is in a state of degradation and requires urgent interventions. Among the needs, a reduction in the high energy consumption and an improvement of the indoor comfort are mandatory. The case study of the "Ex Institute of Zoology of Palermo" shows how it is possible to achieve a reduction in energy consumption and preserve the building's historicity through the estimation of energy loads and the subsequent processing. To quantify the energy savings of the structure, it was necessary to follow a few steps, namely an inspection of the building and an evaluation of its consumption. To elaborate a correct energy analysis, the thermal conductance was calculated by considering measurements over a period of 60 days and proceeding with the calculation of the transmittance. The resulting data are imported in the energy model developed with the TERMUS BIM software. In the case study, a potential energy saving equal to 35% of the current energy consumption can be avoided by replacing the lamps with LED ones, installing photovoltaic panels, replacing the heat pumps with a centralized system and the current fixtures with double thermal break fixtures. These interventions are implemented in compliance with the architectural peculiarities
In Vitro Biocompatibility Evaluation of Nine Dermal Fillers on L929 Cell Line
Objective. Biomaterial research for soft tissue augmentation is an increasing topic in aesthetic medicine. Hyaluronic acid (HA) fillers are widely used for their low invasiveness and easy application to correct aesthetic defects or traumatic injuries. Some complications as acute or chronic inflammation can occur in patients following the injection. Biocompatibility assays are required for medical devices intended for human use, in order to prevent damages or injuries in the host. In this study, nine HA fillers were tested in order to evaluate their cytotoxicity and their effects on L929 cell line, according to the UNI EN ISO 10993 regulation. Methods. Extracts were prepared from nine HA fillers, and MTS viability assay was performed after 24 h, 48 h, and 72 h of exposure of cells to extracts. Cells cultured with HA filler extracts were monitored for up to 72 h, counted, and stained with haematoxylin/eosin in order to evaluate the cell proliferation rate and morphology. Results. None of the filler tested showed a cytotoxic effect. Two samples showed a higher vitality percentage and higher cell number while two samples showed a lower vitality percentage and lower cell number at 72 h. Conclusion. Data obtained suggest that although examined fillers are not cytotoxic, they show different effects on the in vitro cell proliferation rate. In vitro studies of medical devices could lead to important implications since these could aid to predict effects about their in vivo application. These easy and rapid assays could be useful to test new materials intended for human use avoiding animal tests
Analisi biomolecolare di ceppi di Canine Distemper Virus (CDV) in furetti domestici (Mustela putorius furo)
L\u2019agente eziologico del cimurro (CDV) appartiene alla famiglia Paramyxoviridae, genere Morbillivirus ed \ue8 causa di una patologia infettiva e contagiosa in canidi, mustelidi e procionidi. Gli Autori, descrivono un caso clinico di cimurro in due furetti domestici vaccinati con un ceppo Onderstepoort avianizzato. e la caratterizzazione biomolecolare del CDV isolato. I furetti presentavano un quadro clinico caratterizzato da dermatite pruriginosa e squamo-purulenta, alla regione del mento, peri-labiale, peri-vulvare ed al condotto uditivo esterno. I soggetti venivano a morte tre settimane dopo l\u2019esordio dei sintomi. I campioni di croste prelevati sono stati sottoposti ad estrazione degli acidi nucleici ed analizzati mediante RT-PCR per CDV. E\u2019 stata effettuata l\u2019analisi con enzimi di restrizione (RFLP-PCR) di conferma, per discriminare i ceppi vaccinali dai ceppi di campo. I prodotti di amplificazione sono stati purificati e sottoposti a sequenziamento. Le sequenze di 1823 nt del gene H del CDV sono state comparate mediante Clustal X con analoghe sequenze di ceppi di campo e ceppi vaccinali disponibili su GeneBank. Sulla base dei dati ottenuti le sequenze sono risultate appartenenti al lineage Europa, ben segregato dal lineage America-1, che raccoglie i principali ceppi vaccinali avianizzati, e differente dal cluster dei ceppi Rockborn-like. Il sequenziamento ha confermato il risultato ottenuto con la RFLP-PCR e la mancanza di relazione con il ceppo vaccinale inoculato. Le due sequenze ottenute, presentando un\u2019omologia nucleotidica elevata per ceppi isolati da cani in Italia, sono risultate differenti dal lineage Wildlife. Nel furetto l\u2019infezione da cimurro ha un esito fatale quasi nel 100% dei casi e viene controllata attraverso l\u2019uso di vaccini. Questo lavoro rappresenta un contributo alla esigua disponibilit\ue0 bibliografica in merito alle infezioni da CDV nei mustelidi ed implementa i dati disponibili sui ceppi virali circolanti. Il metodo diagnostico descritto rappresenta un sistema rapido e sensibile per la diagnosi dell\u2019infezione da cimurro
An Economic Approach to Size of a Renewable Energy Mix in Small Islands
The importance of renewable energy exploitation reduces the energy dependence on fossil fuels. Despite technological progress, in several remote areas and small islands the energy production is nowadays dominated by the utilization of fossil fuels. With new, increasingly stringent laws on polluting emissions and the need to lower production costs, it is necessary to exploit as many renewable sources as possible. In order to implement these considerations, it was decided to study renewable energy production. The study was carried out by estimating the energy production on a monthly and annual basis considering a mix of three plants, namely marine, solar, and wind. Simulations on wave production were carried out on a new device developed by the research team at the University of Palermo. In order to be able to perform these simulations, input climate data are required. These data are normally available in literature or obtainable by using specific GIS tools. As criterium, the Levelized Cost of Energy, normally applied to a single technology, is extended to the entire energy mix. Minimizing this parameter, the best solution is individuated, and capable of supplying 50% of the summer electrical load with renewable energy sources. The results carried out from a case study based in aeolian islands show that the solar production reaches 10.2%, the wind production reaches 45.47% and sea wave production reaches 3.04%. In this way, the diesel production decreases to 41.29%. This method can be easily applied for several small islands, estimating for several sites the ability to reduce the energy production from fossil fuels
Evidenza di un caso di epatite infettiva del cane in Sicilia
L’Adenovirus Canino di tipo 1 (CAV-1), appartenente al genere Mastadenovirus, famiglia Adenoviridae, è l’agente causale dell’epatite infettiva del cane (ICH). Il virus replica negli endoteli vascolari e negli epatociti, causando epatite necrotico emorragica acuta. I sintomi neurologici sono rari e sono causati da una vasculite del SNC. Negli ultimi anni, la diffusa vaccinazione ha ridotto la circolazione di CAV-1 ed i casi clinici segnalati sono diventati rari ed isolati. In questo lavoro, gli Autori descrivono un caso clinico in un cucciolo di 2 mesi, non vaccinato, con febbre, prostrazione, convulsioni, vomito, diarrea ed esito infausto in una settimana. A seguito dell’esame autoptico, sono stati prelevati campioni di vari organi (cuore, milza, polmone, rene, encefalo, fegato, intestino). Questi sono stati analizzati mediante PCR ed isolamento su colture cellulari sensibili, per la ricerca dei principali agenti virali causa di malattia nel cane: parvovirus, cimurro, CAV-1 e CAV-2, coronavirus, rotavirus. Tutti gli organi esaminati sono risultati positivi sia in PCR che all’isolamento su MDCK solo per CAV-1. Il genoma estratto è stato amplificato secondo la metodica descritta da Hu et al. (2001), in grado di discriminare CAV-1 da CAV-2. L’isolamento su MDCK ha prodotto effetto citopatico al secondo passaggio ed il virus isolato è stato identificato mediante immunofluorescenza diretta e PCR. Il presente lavoro costituisce un contributo alla esigua disponibilità bibliografica sulle infezioni da CAV-1. La vaccinazione sistematica condotta nell’ultimo decennio ha sensibilmente ridotto i casi di malattia. Infatti, gli ultimi casi risalgono al 2001 in Basilicata e Puglia dove sono stati descritti rispettivamente un caso di CAV-1 con sintomatologia classica ed un altro caratterizzato anche da sintomi neurologici. La presente indagine dimostra l’attuale circolazione di CAV-1 e la sporadica comparsa di casi clinici. La vaccinazione sistematica con CAV-2 rimane il mezzo più efficace di protezione della popolazione canina e costituisce l’unico metodo di controllo della malattia
GIV noroviruses and other enteric viruses in bivalves: A preliminary study
We evaluated the presence of the enteric viruses: norovirus, adenovirus, enterovirus, astrovirus, hepatitis A virus, and hepatitis E virus in bivalves using nested PCR methods and cell culture assays. Noroviruses GII.4 and GIV.1, adenoviruses types 1 and 2, hepatitis A, and echovirus type 7 were detected in the shellfish tested, which were often co-infected. This is the first study to detect such a high level of viral contamination in Italian mussels (up to four different viral groups in a single sample), and the first to document the presence of GIV NoV in shellfish
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