91 research outputs found

    Beating the standard quantum limit for binary phase-shift-keying discrimination with a hybrid feed-forward receiver

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    We propose a hybrid feed-forward receiver (HFFRE) for the discrimination of binary phase-shift-keyed coherent states based on the appropriate combination of the displacement feed-forward receiver (DFFRE) and a homodyne-like setup employing a low-intensity local oscillator and photon-number-resolving detectors. We investigate the performance of the proposed scheme addressing also realistic scenarios in the presence of non-unit quantum detection efficiency, dark counts and a visibility reduction. The present HFFRE outperforms the DFFRE in all conditions, beating the standard quantum limit in particular regimes.Comment: 10 pages, 10 figure

    Ultrafiltration (UF) Pilot Plant for Municipal Wastewater Reuse in Agriculture: Impact of the Operation Mode on Process Performance

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    Following increasing interest in the use of UltraFiltration (UF) membrane processes as an alternative advanced disinfection technique, the performance of a UF pilot plant was investigated under two opposite operating conditions ("stressed operating condition" versus "conventional operating condition"). The results indicate that for both conditions, the reclaimed effluent complied with the Italian regulations for unrestricted wastewater reuse (i.e., Total Suspended Solids (TSS) < 10 mg/L; Chemical Oxygen Demand (COD) < 100 mg/L and Escherichia coli < 10 CFU/100 mL). On the other hand, when compared with the Title 22 of the California Wastewater Reclamation Criteria, only the effluent produced under the "conventional operating condition" met the stipulated water quality standards (i.e., TSS and turbidity undetectable and total coliforms < 2.2 CFU/100 mL). It should be noted that, in spite of the nominal cut-off size, total coliforms breakthrough was indeed occasionally observed. A localized membrane pore micro-enlargement mechanism was hypothesized to explain the total coliforms propagation in the ultrafiltered effluent, as monitoring of the membrane permeability and transmembrane pressure highlighted that gel/cake formation had only a minor contribution to the overall membrane fouling mechanism with respect to pore plugging and pore narrowing mechanisms

    Entanglement recovery in noisy binary quantum information protocols via three-qubit quantum error correction codes

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    The task of preserving entanglement against noises is of crucial importance for both quantum communication and quantum information transfer. To this aim, quantum error correction (QEC) codes may be employed to compensate, at least partially, the detriments induced by environmental noise that can be modelled as a bit-flip or a phase-flip error channel. In this paper we investigate the effects of the simple three-qubit QEC codes to restore entanglement and nonlocality in a two-qubit system and consider two practical applications: superdense coding and quantum teleportation. Though the considered three-qubit QEC codes are known to perfectly work in the presence of very small noise, we show that they can avoid the sudden death of entanglement and improve the performance of the addressed protocols also for larger noise amplitudes.Comment: 14 pages, 7 figure

    Hybrid near-optimum binary receiver with realistic photon-number-resolving detectors

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    We propose a near-optimum receiver for the discrimination of binary phase-shift-keyed coherent states employing photon-number-resolving detectors. The receiver exploits a discrimination strategy based on both the so-called homodyne-like and the direct detection, thus resulting in a hybrid scheme. We analyse the performance and the robustness of the proposed scheme under realistic conditions, namely, in the presence of inefficient detection and dark counts. We show that the present hybrid setup is near-optimum and beats both the standard-quantum-limit and the performance of the Kennedy receiver.Comment: 20 pages, 6 figure

    Building Envelope Prefabricated with 3D Printing Technology

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    The Fourth Industrial Revolution represents the beginning of a profound change for the building sector. In the last decade, the perspective of shapes, materials, and construction techniques is evolving fast due to the additive manufacturing technology. On the other hand, even if the technology is growing fast and several 3D printed buildings are being developed worldwide, the potential of concrete 3D printing in building prefabrication remains unexplored. Consequently, the application of new digital fabrication technologies in the construction industry requires a redesign of the construction process and its components. This paper proposes a novel conception, design, and prototyping of a precast building envelope to be prefabricated with extrusion-based 3D concrete printing (3DCP). The new design and conception aim to fully exploit the potential of 3D printing for prefabricated components, especially in terms of dry assembly, speed of implementation, reusability, recyclability, modularity, versatility, adaptability, and sustainability. Beyond the novel conceptual design of precast elements, the research investigated the 3D printable cementitious material based on a magnesium potassium phosphate cement (MKPC), which was devised and tested to ensure good performances of the proposed component. Finally, a prototype has been realised in scale with additive manufacturing technology in order to verify the printability and to optimize the extruder path. This study leads us to believe that the combined use of prefabricated systems, construction automation, and innovative materials can decisively improve the construction industry's sustainability in the future

    Kinetics of PAA Demand and its Implications on Disinfection of Wastewaters

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    Abstract Disinfectant demand and microbial inactivation rate are essential issues for assessing disinfection performance and proper design of disinfecting systems. In the United Kingdom and Italy, peracetic acid (PAA) has recently become an accepted disinfectant for treating wastewaters prior to reuse in agriculture, and its use is likely to spread worldwide due to its efficacy as well as the benign nature of the by-products produced. In this paper, overall PAA demand during the advanced disinfection of municipal wastewater for agricultural reuse was evaluated under different experimental conditions. Batch tests were carried out using primary and secondary settled effluents sampled at the City of Taranto municipal wastewater treatment plant. PAA dosages ranged from 1.5 to 8.5 mg/L and from 21 to 40 mg/L for the secondary and primary settled effluents, respectively. Residual PAA was measured after contact times ranging from 1 to 60 min. Results showed that after a strong and almost instantaneous initial disinfectant consumption, the PAA consumption followed first-order kinetics with both effluents. The effluent characteristics affected the values of the parameters in the consumption model. PAA disinfection efficacy was assessed in terms of total coliform and Escherichia coli indicator organism reduction; better results were achieved with the latter. The approximate solution of Hom's model established by Haas and Joffe was used to model inactivation kinetics of both microbial targets
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