2,097 research outputs found
Nanomaterials and nanofabrication for next generation photovoltaics
No full textOn December 2015, almost 200 countries were represented in Paris, discussing on the topics of climate change and Kyoto Protocol. According to the organizing committee at the outset of the talks, the expected key result was an agreement to set a goal of limiting global warming to less than 2°C compared to pre-industrial levels [1]. In order to reach this goal, huge cut on polluted emissions has to be done, finding new resources to produce energy. Photovoltaics is a sustainable and environmentally clean energy source that has the potential to become one of the main ones, in the near future. In order for this to happen, photovoltaics needs to be economically competitive with other conventional energy sources: despite the price of conventional Si solar cells dropped from ~4 USD/WP to ~0.54 USD/WP in the last 15 years [2], the use of new materials to get even more low-cost solar cells created the field of the so-called “new generation photovoltaics”.
Organic (polymeric and small molecules) solar cells have been extensively investigated, in the last years, not only for the potential low fabrication costs, but also for the possibility of building integration and for the solution process realization that allows spray, Roll-toroll and printing techniques, over rigid or flexible substrates. Moreover, perovskite solar cells, that are also compatible with the above mentioned production methods, recently outperformed multicrystalline Si, showing an impressive certified efficiency of 22.1 % [3]. This “new gen” solar cells strictly rely on research performed in the nanometric world: the typical thickness of an active layer for organic solar cell is hundreds of nanometers; phase separation between different components of polymeric solutions are investigated by the mean of Atomic Force Microscopy, which allows to see features in the order of some nanometers; perovskite is likely deposited on top of scaffold with nanometric pores. So, integrate nanomaterials and nanofabrication steps in the realization of such solar cells is of great interest.
In this work, the possible interactions of nanomaterials as Carbon Nanotubes (CNTs) and Nanoporous Alumina, as well as the integration of nanotechnology process such as Nanoimprint Lithography, have been investigated in the field of new gen solar cells. A thorough research on Carbon nanotubes (CNTs) has been carried out to realize semitransparent electrodes to be used as contacts in an organic solar cell. A “two temperature zone” Chemical Vapour Deposition (CVD) set-up is assembled to synthesize CNTs directly on top of Fluorine Doped Tin Oxide and standard glass. The transparency of the asprepared contacts is increased by the mean of a laser patterning technique. An additional technique used to deposit a very thin layer of Nickel, to enhance the conductivity of such semitransparent electrodes, is also presented.
The necessity of decreasing the roughness of the CNTs based electrodes, in order to prevent short circuits in organic solar cells, leads to the development of a spray deposition technique of nanotubes solutions on top of glass substrates. The use of different solutions, with and without the addition of surfactants, as well as the upgrade of the spray set-ups and the design of appropriate metal contacts for inverted organic P3HT:PCBM solar cells are shown.
The inverted architecture of bulk heterojunction solar cell is used also in combination with the Nanoimprint Lithography Technique (NILT): the creation of a pattern of nanometers size on the polymer surface, in order to realize a Photonic Crystal effect designed by optical simulations, is carried out through several technology obstacles, for each of which is given a proper solution.
Lastly, scaffolds of ordered Nanoporous Alumina, realized through the anodization of pure and evaporated Aluminium on glass, are used for the growth of perovskite active layers that are characterized by absorbance measurements
Italian breed-specific legislation on potentially dangerous dogs (2003): assessment of its effects in the city of Florence (Italy)
No full textCanine aggression is a very discussed topic, especially when a person is injured. The problem of dog bites towards human beings must be tackled and scientifically analysed, in order to address the policy makers to effective measures. The aim of this study was to assess the effects of Italian breed-specific legislation on potentially dangerous dogs (Sirchia’s Ordinance issued on the 9th September 2003 called “Protection of the public safety against the risk of aggressions by potentially dangerous dogs”) on the trend of dog bites towards people in the city of Florence (Italy). Data for the current study were collected by the Veterinary and Urban Health, Local Sanitary Enterprise 10 in the city of Florence (Italy). Reports drew from the certifications of medical reports coming from different Hospital Emergency Departments in Florence, from the denunciation done at the canine registry office, and from the observational reports carried out at the observatory for the prophylaxis of the rabies. Reports referred to dog bites occurred in the city of Florence from September 2002 to August 2005. In total, 556 cases were gathered. The characteristics of injuries, dogs, owners and victims involved in dog bites in the year preceding the Sirchia’s Ordinance were compared to the same characteristics in the two years after the issue of such Ordinance (short and long-term effects) using the c2 test (p<0.05).The findings suggest that the above-mentioned ordinance has not caused any significant change on the trend of dog bites in the taken sample, nor in the short-term neither in the long-term. In fact, even if a numerical decrease has been observed in the period following the ordinance, a trend of reduction was already in progress since 1986. In addition, the characteristics of owners, injured people and dogs involved in the aggressive episodes remained unvaried, apart from a decrease in minor injuries. Finally, after the Ordinance the number of dog owners whose personal details were unknown increased. These findings suggest that restrictive legislative measures regarding potentially dangerous dogs are not effective for the control of canine aggression towards people
Rapid non-contact detection of chemical warfare agents by laser photoacoustic spectroscopy
No full textNerve agents have recently been used in battlefield operations, espionage wars, and terrorist attacks. These compounds, like some pesticides, cause organophosphate poisoning. The rapid, noncontact detection of a sarin simulant in the liquid phase has been demonstrated at the Diagnostics and Metrology Laboratory of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development using laser photoacoustic spectroscopy, an infrared absorption technology. The first measurements, carried out with an experimental system based on a quantum cascade laser and developed for the assessment of food authenticity in the "fingerprint region", show that a detection limit of one nanolitre is within the reach of the instrument when chemometric analysis is applied
Postal de Claudio Vivas a Maruja Vieira, junio 23 de 1955
No full textPostal de Claudio Vivas a Maruja Vieira, felicitándola por el reconocimiento que le fue otorgado a la autora de poemasPostcard from Claudio Vivas to Maruja Vieira, congratulating her for the recognition given to the author of poems.Publicación, fondo Maruja Vieira, carpeta 1, folio
Development and Test of Low-Cost Multi-Channel Multi-Frequency Lock-In Amplifier for Health and Environment Sensing
No full textOptical-based sensing techniques and instruments, such as fluorometric systems, absorbance-based sensors, and photoacoustic spectrometers, are important tools for detecting food fraud, adulteration, and contamination for health and environmental purposes. All the aforementioned optical equipments generally require one or more low-frequency Lock-In Amplifiers (LIAs) to extract the signal of interest from background noise. In the cited applications, the required LIA frequency is quite low (up to 1 kHz), and this leads to a simplification of the hardware with consequent good results in portability, reduced size, weight, and low-cost characteristics. The present system, called ENEA DSP Box Due, is based on a very inexpensive microcontroller proto-board and can replace four commercial LIAs, resulting in significant savings in both cost and space. Furthermore, it incorporates a dual-channel oscilloscope and a sinusoidal function generator. This article outlines the architecture of the ENEA DSP Box Due, its electrical characterization, and its applications within a project concerning laser techniques for food and water safety
Survey of undesirable behaviors displayed by potential guide dogs with puppy walkers
No full textThis research aimed to identify the frequency and type of undesirable behaviors observed by guide dog puppy walkers and management strategies used by them during the puppy-walking period. All members of 36 puppy-walking families (N = 96), recruited from the National School of Guide Dogs for Blind People in Florence (Italy), completed an 80-item questionnaire. This sampling represented homes caring for 28 Labrador Retrievers, 6 Golden Retrievers, and 2 German shepherd dogs. Of these dogs, 47.2% (n = 17) were males and 52.8% (n = 19) females, and 66.7% (n = 24) were between 7 and 12 months old.Three categories of undesirable behaviors were recorded. First, behaviors considered inconsequential to the guide dog role were: digging (11.8%, n = 11); chewing objects (4.4%, n = 4); stealing or begging for food (3.1%, n = 3); liking people (5.9%, n = 5); getting on furniture (4.4%, n = 4); defending territory (2.8%, n = 2); and coprophagia (5.9%, n = 5). Second, the following behaviors considered easily resolvable through training were recorded: lack of recall (8.9%, n = 10); pulling on lead (11.8%, n = 11); jumping up (28.1%, n = 30); barking at other dogs (5.9%, n = 5); chewing the leash (1.5%, n = 1); and house soiling (5.9%, n = 5). Third, these potentially disqualifying behaviors were observed: scavenging (17.7%, n = 17); aggressive barking, growling, and biting (10.4%, n = 10); and fear of thunderstorms (6.2%, n = 6); loud noises (32.3%, n = 31); men (2.1%, n = 2); women (3.1%, n = 3); and people with unusual clothes (6.2%, n = 6). None of the puppies was reported to be fearful of children.Overall, 66.7% (n = 66) of respondents recorded at least 1 undesirable behavior. However, only few of them might lead to disqualification. The results suggest that most of the puppies were well socialized to people and not fearful.Puppy walkers could contribute to the early assessment of potential behavioral problems, which are a major cause of disqualifying guide dogs.<br/
Rapid identification of Bartonella henselae by real-time polymerase chain reaction in a patient with cat scratch disease
No full textWe report a localized submandibular lymph node infection in a patient with cat scratch disease. Directly performing real-time polymerase chain reaction assay on the biopsy sample, Bartonella henselae DNA was simultaneously detected and identified. (c) 2005 Elsevier Inc. All rights reserved
“Dialogue between Translators and Authors. The Example of Claudio Magris”
No full textThe paper focuses on the forms of cooperation between authors and their translator(s) in all cases in which the two operate simultaneously. This issue is explored on the example of the Trieste-born author Claudio Magris, who cultivates a very close relationship with most of his translators.
Writing and translation have been coexisting in this author throughout his career and have resulted in the heightened sensitivity of Magris the author with regards to translation, as the first part of the analysis shows. The second part describes the dialogue between Magris and the translators of his works, and ends with the more general question of the significance and role of such a form of exchange
Consideraciones sobre la poética de Claudio Rodríguez
No full textThe purpose of this paper is to study the poetics of Claudio Rodríguez, delimiting its components and trying to clarify them and to present them as a whole. The author left some pages written on his conception of poetry that encourage reflection and, in some cases, interpretation. So with his conception of poetry as a gift and inebriation, as an alliance and condemnation or celebration (giving title to his collections of poems), or with notions such as «participation», «living contemplation», «living expression » or «personal rhythm» that make up his way of understanding the poetic process.El propósito de este artículo es estudiar la poética de Claudio Rodríguez, deslindando sus componentes y tratando de clarificarlos y presentarlos en su conjunto. El autor dejó escritas algunas páginas sobre su concepción de la poesía que animan a la reflexión y, en algunos casos, a la interpretación. Así sucede con su concepción de la poesía como un don y una ebriedad, como alianza y condena o como celebración (que dan título a sus poemarios), o con nociones como las de «participación», «contemplación viva», «expresión viva» o «ritmo personal», que configuran su forma de entender el proceso poético
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