1,948 research outputs found
Polarization entangled state measurement on a chip
The emerging strategy to overcome the limitations of bulk quantum optics
consists of taking advantage of the robustness and compactness achievable by
the integrated waveguide technology. Here we report the realization of a
directional coupler, fabricated by femtosecond laser waveguide writing, acting
as an integrated beam splitter able to support polarization encoded qubits.
This maskless and single step technique allows to realize circular transverse
waveguide profiles able to support the propagation of Gaussian modes with any
polarization state. Using this device, we demonstrate the quantum interference
with polarization entangled states and singlet state projection.Comment: Revtex, 5+2 pages (with supplementary information), 4+1 figure
2D equivalent linear analysis for the seismic vulnerability evaluation of multi-propped retaining structures
The evaluation of the seismic behaviour of underground structures represents one of the most actual seismic geotechnical and structural engineering research topics about the study of the complex phenomena of soil-structural interaction. In the last decades, different types of simplified and numerical approaches have been developed for the correct analysis of the seismic vulnerability of these important infrastructures and a series of laboratory tests for the seismic behaviour characterization of the soils (resonant column test, etc.) and of the coupled soil-structure system (centrifuge test, etc.) have been conducted, especially after the recent strong earthquakes where the underground structures have been subjected to significant damages. In the same way, in the last few years, the International Codes are beginning to pay attention to the concepts of the seismic design of these structures. Despite the significant development of knowledge, described above, still remain open several uncertainties of the correct reproduction of the underground structures behaviour under seismic load. In this paper, the evaluation of the seismic behaviour of a multi-propped retaining structure was conducted, considering the soil-structure interaction effects. The results of the 2D equivalent linear analysis are analysed in terms of bending moment acting on the concrete retaining walls.LâĂ©valuation du comportement sismique des structures souterraines reprĂ©sentent un des sujets de
recherche les plus courants sismique, gĂ©otechnique et de construction, qui concerne lâĂ©tude du phĂ©nomĂšne
complexe de lâinteraction sol-structure. Pendant les derniĂšres dĂ©cennies, diffĂ©rents types dâapproches simples et
numeriques ont été développés pour une analyse exacte de la vulnérabilité sismique de ces infrastructures
importantes et encore une série de tests de laboratoire pour la caractérisation du comportement sismique du sols
(test de colonne résonnante etc.) et du systÚme couplé du sol-structure (test de centrifugation etc.) ont été menées,
aprĂšs le fort tremblement de terre oĂč les structures souterraines ont subi des dommages importants. De la mĂȘme
maniĂšre, pendant les dĂšrnieres annĂ©es, les Codes Internationales ont commencĂ© a prĂȘter plus dâattention aux
concepts de désign sismique de ces structures. Malgré la considÚrable connaissance, décrit ci-dessus, il y a quand
mĂȘme de lâincertitude sur la correcte reproduction du comportement des structures sous charge sismique. Dans
cet article, il a Ă©tĂ© menĂ© lâevaluation du comportement sismique des structures de soutenement multi-etayĂ©,
considĂ©rant que les effets de lâinteraction sol-structure. Les resultats de lâanalyse linĂ©aire 2D equivalente sont
analysées en termes de moment de flexion agissant sur les murs de soutÚnement en béton
Environmental performances in green labels for hotels â a critical review
The global attention towards climate change has led national governments and the international community to the definition of plans aiming to reduce greenhouse gas emissions in all economic sectors. Recently, attention has focused also on the tourism sector, and especially on the lodging industry, which consumes high amounts of resources and energy to satisfy guests expectations in terms of offered services and comfort conditions. In this sector, eco-certifications or green labels are spreading, perceived as useful marketing tools to communicate the hoteliersâ environmental efforts to consumers, who are becoming more and more sensitive to ecological matters. However, the wide offer of green labels and the lack of appropriate information are contributing to increase costumersâ confusion and perception of real âgreenâ. The present paper focuses its attention on a set of currently available tools to evaluate the environmental performances of hotels, in order to enquire if and to which extent they are able to inform about the sustainability of accommodation structures. Starting from the wide number of certification schemes available on the market, 19 multi-attribute, third-party green labels were compared, aiming to explore the role that energy efficiency measures play in the certification procedure
The advantages of fly ash use in concrete structures
In this paper the use of fly ash for particular High Strength Concrete (HSC) realizations is investigated. The use of fly ash as a partial replacement of Portland cement in HSC seems a valid solution in particular for a sustainable construction design, considering the interesting HSC performances (in terms of strength and durability) and the economic aspects (in terms of waste material's reuse from industrial process). Fly ashes have been employed in the past especially for underground structures. Nowadays, their use is under evaluation also for elevation structures. In this paper, the most important technical regulations about the use of fly ash for the concrete mix design are discussed. The increase of the mechanical resistance, the better protection against chemical agents attacks and freezing - thawing cycles using fly ashes are also show. Moreover, in comparison to the fresh concrete, the benefits related to the minor water/cement (w/c) ratio are presented, in the same workability conditions. Additional considerations are carried out about the hydration process: the mixture produces less heat for the lowering of the C3A and C3S percentages using fly ash. Finally, a greater concrete impermeability obtained using fly ash, due to the presence of a lower hydrolysis content, which leads to an increment of the cement paste porosity, has been evidenced. All of mentioned benefits shows the fly ash use in the High Strength Concrete (HSC) is a valid solution against many problems interested negatively the concrete mix - design and the mix - production
The use of fly ash in high strength concrete mix design
In this paper the use of fly ash for particular High Strength Concrete (HSC) realizations is investigated. The use of fly ash as a partial replacement of Portland cement in HSC seems a valid solution in particular for a sustainable construction design, considering the interesting HSC performances and the economic aspects. Obviously the advantages demonstrated for the underground constructions can be also evaluated for the structures in elevation. In this paper the most important technical regulations about the use of fly ash for the concrete mix design are discussed and itâs shown the increase of the mechanical resistance and the better protection against the chemical agents attacks and against the freezing and thawing cycles using fly ash. Moreover, in comparison to the fresh concrete, itâs presented the benefits related to the minor ratio water/cement (defined by w/c) in the same conditions of workability. Additional considerations are carried out about the hydration process: the mixture produces less heat for the lowering of the C3A and C3S percentages using fly ash. Finally, a greater concrete impermeability obtained using fly ash, due to the presence of a lower hydrolysis content, which leads to an increment of the cement paste porosity, has been evidence
Discrete transverse superconducting modes in nano-cylinders
Spatial variation in the superconducting order parameter becomes significant
when the system is confined at dimensions well below the typical
superconducting coherence length. Motivated by recent experimental success in
growing single-crystal metallic nanorods, we study quantum confinement effects
on superconductivity in a cylindrical nanowire in the clean limit. For large
diameters, where the transverse level spacing is smaller than superconducting
order parameter, the usual approximations of Ginzburg-Landau theory are
recovered. However, under external magnetic field the order parameter develops
a spatial variation much stronger than that predicted by Ginzburg-Landau
theory, and gapless superconductivity is obtained above a certain field
strength. At small diameters, the discrete nature of the transverse modes
produces significant spatial variations in the order parameter with increased
average magnitude and multiple shoulders in the magnetic response.Comment: 10 pages, 8 figure
Exploitation of dynamic simulation to investigate the effectiveness of the Smart Readiness Indicator: application to the Energy Center building of Turin
To achieve the energy and emissions reduction goals for the building sector, actions are needed to improve energy efficiency and occupantsâ wellbeing. To increase the uptake of smart technologies and the awareness upon their benefits, in line with the smart building revolution that is starting, the EPBD recast introduced the Smart Readiness Indicator (SRI) as a tool to evaluate the capability of buildings to easily adapt to both energy systems and occupantsâ needs. However, there is a growing interest in studying the SRI features in terms of performance assessment, and, thus, dynamic simulation models can be exploited to better analyze its points of strength and weakness. The Energy Center building of Turin was chosen as case study. By means of EnergyPlus modeling, the current situation was simulated, as well as different scenarios of energy management and control, evaluating to what extent these actions can influence the overall SRI assessment. The analysis allowed to deepen and comment on the effectiveness of the SRI of being a real tool of building behavior assessment, able to link the indicator itself with the energy needs of the building and to understand if and how the indicator is sensible to energy needs variations
Oral Supplementation With Sucrosomial Ferric Pyrophosphate Plus L-Ascorbic Acid to Ameliorate the Martial Status: A Randomized Controlled Trial
Altered martial indices before orthopedic surgery are associated with higher rates of complications and greatly affect the patient's functional ability. Oral supplements can optimize the preoperative martial status, with clinical efficacy and the patient's tolerability being highly dependent on the pharmaceutical formula. Patients undergoing elective hip/knee arthroplasty were randomized to be supplemented with a 30-day oral therapy of sucrosomial ferric pyrophosphate plus L-ascorbic acid. The tolerability was 2.7% among treated patients. Adjustments for confounding factors, such as iron absorption influencers, showed a relevant response limited to older patients ( 65 65 years old), whose uncharacterized Hb loss was averted upon treatment with iron formula. Older patients with no support lost -2.8 \ub1 5.1%, while the intervention group gained +0.7 \ub1 4.6% of circulating hemoglobin from baseline (p = 0.019). Gastrointestinal diseases, medications, and possible dietary factors could affect the efficacy of iron supplements. Future opportunities may consider to couple ferric pyrophosphate with other nutrients, to pay attention in avoiding absorption disruptors, or to implement interventions to obtain an earlier martial status optimization at the population level
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