4,531 research outputs found
A Schematic Framework to Assess Mini Hydro Potentials in the Italian Regional Energy and Environmental Plans
In compliance with EU legislation (Directive 2009/28/EC, that establishes for each Member State a target calculated according to the share of energy from renewable sources in its gross final consumption to 2020) and Italian regulatory framework (DM 15/03/12- Burden Sharing, that defines the regional objectives regarding renewable sources), each Italian Region must develop its own Regional Energy and Environmental Plan (PEAR). In order to promote the renewable energy sources (RES) production and to achieve a better energy efficiency use, the PEARS should propose to adopt a distributed multi generation (DMG) strategy.
The main aim of this paper is a preliminary assessment of mini hydro potential and perspectives (P <1 MW) in Italian PEARS. Mini hydro is a mature and developed technology in Italy, and it represents a valiant opportunity for both local territories and the whole national system. Furthermore, thanks to its small size (low economic investment and environmental impact) and its versatility, it has the characteristics for a long-term development with direct industrial implications (i.e. energy cooperative and short supply chain). Specifically, the PEARS of four Regions were analysed, identifying the different information about mini hydro and comparing characteristics and potential.
The results obtained are summarized in a schematic framework useful to draw a preliminary PEARS guideline that indicates strategies and policies, harmonizing public and private initiatives and structuring a local-scale economy through a mini hydro based DMG
Entanglement generation in relativistic quantum fields
We present a general, analytic recipe to compute the entanglement that is
generated between arbitrary, discrete modes of bosonic quantum fields by
Bogoliubov transformations. Our setup allows the complete characterization of
the quantum correlations in all Gaussian field states. Additionally, it holds
for all Bogoliubov transformations. These are commonly applied in quantum
optics for the description of squeezing operations, relate the mode
decompositions of observers in different regions of curved spacetimes, and
describe observers moving along non-stationary trajectories. We focus on a
quantum optical example in a cavity quantum electrodynamics setting: an
uncharged scalar field within a cavity provides a model for an optical
resonator, in which entanglement is created by non-uniform acceleration. We
show that the amount of generated entanglement can be magnified by initial
single-mode squeezing, for which we provide an explicit formula. Applications
to quantum fields in curved spacetimes, such as an expanding universe, are
discussed.Comment: 8 pages, 2 figures, Ivette Fuentes previously published as Ivette
Fuentes-Guridi and Ivette Fuentes-Schuller; v2: published version (online),
to appear in the J. Mod. Opt. Special Issue on the Physics of Quantum
Electronic
RES (Renewable Energy Sources) Availability Assessments for Eco-fuels Production at Local Scale: Carbon Avoidance Costs Associated to a Hybrid Biomass/H2NG-based Energy Scenario
Eco-fuels are a sustainable solution to face increasing global energy consumptions and GHG emissions. This work was firstly focused on available renewables assessment linked to a local dimension. Furthermore, identifying the potential Eco-fuels capability, it was discussed how the capital expenditure for infrastructures is associated with carbon avoidance costs.
A coastal municipality and an inland one, located in Central Italy, are selected as case studies.
In order to assess PV and agro-forestry residues availability, a GIS-based analysis was performed. In this framework, a new energy scenario, based on H2NG blends use and ligneous biomass conversion, was presented. Specifically, the hydrogen for NG enrichment was produced by renewable electricity, while biomass energy content was evaluated considering gasification process.
Finally, the governmental incentive schemes incidence (in force for bioenergy and hypothesized for hydrogen) on investments economic sustainability and on infrastructure deployment was compared in terms of carbon avoidance costs
Single Cylinder Internal Combustion Engine Fuelled with H2NG Operating as Micro-CHP for Residential Use: Preliminary Experimental Analysis on Energy Performances and Numerical Simulations for LCOE Assessment
The paper presents data resulting by the preliminary experimental campaign performed on a micro CHP (combined heat and power) pre-commercial version (5 kWel) designed for dwellings. The engine employs the lubricant oil as the jacket coolant to simplify the heat recovery architecture and it was equipped by a condensing heat exchanger as well. The tests have been carried out at rated and partial load up to 2.9 kWel (59% of rated load) in condensing mode, fuelling the NG engine with hydrogen percentages equal to 0% vol. and 15% vol. In order to evaluate the CHP energy performance, the analysis was conducted for 160 h, using an alkaline electrolyser for hydrogen production, a static heat meter and two mass flow meters for both hydrogen and NG. The aim of this paper is to illustrate how the use of the hydrogen enrichment in a micro CHP plant, based on ICE technology, represents a foreseeable bridge solution to the forthcoming SOFC deployment
Architectural Considerations in Hybrid Quantum-Classical Networks
Three network architectures, compatible with passive optical networks, for future hybrid quantum-classical networks are proposed and compared. These setups rely on three different schemes for quantum key distribution (QKD): BB84, entanglement-based QKD, and measurement-device-independent QKD (MDI-QKD). It turns out that, while for small-to-moderatesize networks BB84 supports the highest secret key generation rate, it may fail to support large numbers of users. Its cost implications are also expected to be higher than other setups. For large networks, MDI-QKD offers the highest key rate if fast single-photon detectors are employed. Entanglement-based networks offer the longest security distance among the three setups. MDI-QKD is, however, the only architecture resilient to detection loopholes and possibly the most favorable with its less demanding end-user technology. Entanglement-based and MDI-QKD setups can both be combined with quantum repeater systems to allow for long-distance QKD with no trust constraints on the service provider
Computational approaches to shed light on molecular mechanisms in biological processes
Computational approaches based on Molecular Dynamics simulations, Quantum Mechanical methods and 3D Quantitative Structure-Activity Relationships were employed by computational chemistry groups at the University of Milano-Bicocca to study biological processes at the molecular level. The paper reports the methodologies adopted and the results obtained on Aryl hydrocarbon Receptor and homologous PAS proteins mechanisms, the properties of prion protein peptides, the reaction pathway of hydrogenase and peroxidase enzymes and the defibrillogenic activity of tetracyclines. © Springer-Verlag 2007
Lifetime prevalence and help seeking behavior in physical marital violence
OBJECTIVE: To estimate the lifetime prevalence of physical marital violence among women from a low-income urban community and to investigate help-seeking behavior among victims. METHODS: This is the Brazilian pilot cross-sectional study for an international multicenter study conducted in 1999, and is based on a probabilistic cluster sample from the municipality of Embu, SĂŁo Paulo State. We considered as eligible women aged 15 to 49 years, living with children under age 18 years, who had lived with a husband or partner in lifetime. Information was collected using standardized questionnaires (n=86), administered by trained interviewers. We investigated three types of physical violence: severe (kicking, hitting with fist, beating, and/or use/threat to use weapon), non-severe (slapping in the absence of severe violence), and any type (severe and/or non-severe and/or other physical aggressions spontaneously referred), as well as the type of help sought by the victim (from people or institutions). We calculated frequency and 95% confidence intervals for each type of violence. RESULTS: Subjects reported slapping (32.6%), hitting with fist (17.5%), beating (15,2%), use/threat to use weapon (13.9%), and kicking (10.6%). Prevalence of marital violence was high: 22.1% (13.3-30.9) for severe violence, 10.5% (4.0-17.0) for non-severe violence, and 33.7% (32.7-34.7) for any type of violence. Victims of severe violence were more likely to seek help from the police (36.8%) or from traditional healers (21.1%) than from health care facilities (5.3%), despite the availability of these services in the area. CONCLUSIONS: Physical marital violence is frequent and severe among the population studied, and help was sought preferentially from the police or traditional healers rather than from health care services.OBJETIVO: Estimar a prevalĂȘncia de violĂȘncia conjugal fĂsica ao longo da vida em mulheres de comunidade urbana de baixa renda e identificar os tipos de ajuda procurados pelas vĂtimas. MĂTODOS: Trata-se de estudo-piloto brasileiro de corte transversal, vinculado a projeto multicĂȘntrico internacional conduzido em 1999, com amostra probabilĂstica de conglomerados no municĂpio de Embu, Estado de SĂŁo Paulo. Foram considerados elegĂveis os domicĂlios com mulheres de 15 a 49 anos, que residissem com filho/filha <18 anos e tivessem vivido com algum marido/companheiro ao longo da vida. Entrevistadoras treinadas aplicaram questionĂĄrios padronizados (n=86). TrĂȘs tipos de violĂȘncia conjugal fĂsica sofrida ao longo da vida foram investigados: grave (chute, soco, espancamento e/ou uso/ameaça de uso de arma), nĂŁo grave (tapa na ausĂȘncia de violĂȘncia grave) e algum tipo (grave e/ou nĂŁo grave, alĂ©m de outras formas de agressĂŁo fĂsica espontaneamente referidas) e os tipos de ajuda procurada (pessoas e instituiçÔes). Foram calculadas as freqĂŒĂȘncias dos tipos de violĂȘncia e respectivos intervalos de confiança de 95%. RESULTADOS: As entrevistadas referiram tapa (32,6%), soco (17,5%), espancamento (15,2%), uso/ameaça de arma (13,9%) e chute (10,6%). Foram altas as taxas de prevalĂȘncia de violĂȘncia conjugal: grave 22,1% (13,3-30,9), nĂŁo grave 10,5% (4,0-17,0) e algum tipo 33,7% (32,7-34,7). VĂtimas de violĂȘncia grave procuraram ajuda mais freqĂŒentemente da polĂcia/delegacia (36,8%) ou de curandeiros/benzedeiras/pais de santo (21,1%) que de centros de saĂșde (5,3%), apesar da disponibilidade desses serviços na regiĂŁo. CONCLUSĂES: A violĂȘncia conjugal fĂsica ao longo da vida Ă© freqĂŒente e grave na comunidade estudada, sendo que a procura de ajuda foi direcionada mais freqĂŒentemente Ă polĂcia/delegacia ou a curandeiros/benzedeiras/pais de santo do que a centros de saĂșde.Universidade Federal de SĂŁo Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PsiquiatriaUniversidade Presbiteriana Mackenzie Faculdade de PsicologiaUNIFESP, EPM, Depto. de PsiquiatriaSciEL
Scattering of Plane Waves in Self-Dual Yang-Mills Theory
We consider the classical self-dual Yang-Mills equation in 3+1-dimensional
Minkowski space. We have found an exact solution, which describes scattering of
plane waves. In order to write the solution in a compact form, it is
convenient to introduce a scattering operator . It acts in the direct
product of three linear spaces: 1) universal enveloping of Lie algebra,
2) -dimensional vector space and 3) space of functions defined on the unit
interval.Comment: 16 pages, LaTeX fil
Mechanistic and Physiological Implications of the Interplay among Iron-Sulfur Clusters in [FeFe]-Hydrogenases. A QM/MM Perspective
Key stereoelectronic properties of Desulfovibrio desulfuricans [FeFe]-hydrogenase (DdH) were investigated by quantum mechanical description of its complete inorganic core, which includes a Fe6S6 active site (the H-cluster), as well as two ancillary Fe4S4 assemblies (the F and F' clusters). The partially oxidized, active-ready form of DdH is able to efficiently bind dihydrogen, thus starting H-2 oxidation catalysis. The calculations allow us to unambiguously assign a mixed Fe(H)Fe(I) state to the catalytic core of the active-ready enzyme and show that H-2 uptake exerts subtle, yet crucial influences on the redox properties of DdH. In fact, H-2 binding can promote electron transfer from the H-cluster to the solvent-exposed F'-cluster, thanks to a 50% decrease of the energy gap between the HOMO (that is localized on the H-cluster) and the LUMO (which is centered on the F'-cluster). Our results also indicate that the binding of the redox partners of DdH in proximity of its F'-cluster can trigger one-electron oxidation of the H-2-bound enzyme, a process that is expected to have an important role in H-2 activation. Our findings are analyzed not only from a mechanistic perspective, but also in consideration of the physiological role of DdH. In fact, this enzyme is known to be able to catalyze both the oxidation and the evolution of H-2, depending on the cellular metabolic requirements. Hints for the design of targeted mutations that could lead to the enhancement of the oxidizing properties of DdH are proposed and discussed
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