11,384 research outputs found

    Estimation of the gravitational wave polarizations from a non template search

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    Gravitational wave astronomy is just beginning, after the recent success of the four direct detections of binary black hole (BBH) mergers, the first observation from a binary neutron star inspiral and with the expectation of many more events to come. Given the possibility to detect waves from not perfectly modeled astrophysical processes, it is fundamental to be ready to calculate the polarization waveforms in the case of searches using non-template algorithms. In such case, the waveform polarizations are the only quantities that contain direct information about the generating process. We present the performance of a new valuable tool to estimate the inverse solution of gravitational wave transient signals, starting from the analysis of the signal properties of a non-template algorithm that is open to a wider class of gravitational signals not covered by template algorithms. We highlight the contributions to the wave polarization associated with the detector response, the sky localization and the polarization angle of the source. In this paper we present the performances of such method and its implications by using two main classes of transient signals, resembling the limiting case for most simple and complicated morphologies. Performances are encouraging, for the tested waveforms: the correlation between the original and the reconstructed waveforms spans from better than 80% for simple morphologies to better than 50% for complicated ones. For a not-template search this results can be considered satisfactory to reconstruct the astrophysical progenitor

    A deeper insight into quantum state transfer from an information flux viewpoint

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    We use the recently introduced concept of information flux in a many-body register in order to give an alternative viewpoint on quantum state transfer in linear chains of many spins.Comment: 6 pages, 3 figures, RevTeX

    Continuous production of KNO3 nanosalts for the fertilization of soil by means of a Spinning Disk Reactor

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    In this study the production of high soluble material nanoparticles was successfully performed by means of a spinning disk reactor (SDR). This result was possible due to the use of a potassium nitrate saturated solution, which was continuously recycled back to the reactor after removal of the produced solid nanoparticles. Several process configurations were checked. It appears to be mandatory that the recycled saturated solution must be free of residual nanoparticles since their presence would lead to heterogeneous nucleation. In this respect, a small amount of nitric acid was added to the stream to permit the residual nanoparticle dissolution. Moreover, a spiral wounded piping system was developed in order to increase both the contact time and the mixing condition of the saturated solution with the added acid before entering the SD

    About the limits of microfiltration for the purification of wastewaters

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    In the past, microfiltration was widely used as a pretreatment step for wastewater stream purification purposes. Experiences performed during the last years shows that microfiltration fails to maintain its performances for longer period of times. Many case studies demonstrate that the adoption of microfiltration leads to the failure of the overall process; the severe fouling of the microfiltration membranes leads to high operating costs with the consequence to make the treatment of the wastewater economically unfeasible. The boundary flux concept is a profitable tool to analyze fouling issues in membrane processes. The boundary flux value separates an operating region characterized by reversible fouling formation from irreversible one. Boundary flux values are not content, but function of time, as calculated by the subboundary fouling rate value. The knowledge of both parameters may fully describe the membrane performances in sub-boundary operating regimes. Many times, for wastewater purification purposes, ultrafiltration membranes appear to be suits better to the needs, even they exhibit lower permeate fluxes compared to microfiltration. Key to this choice is that ultrafiltration appears to resist better to fouling issues, with a limited reduction of the performances as a function of time. In other words, it appears that ultrafiltration exhibit higher boundary flux values and lower sub-boundary fouling rates. In this work, after a brief introduction to the boundary flux concept, for many different wastewater streams (more than 20, produced by the most relevant industries in food, agriculture, manufacture, pharmaceutics), the boundary flux and sub-boundary fouling rate values of different microfiltration and ultrafiltration membranes will be discussed and compared. The possibility to successfully use microfiltration as a pretreatment step strongly depends on the feedstock characteristics and, in detail, on the particle size of the suspended matter. In most cases, microfiltration demonstrates to be technically unsuitable for pretreatment purposes of many wastewater streams; as a consequence, the adoption of microfiltration pushes operators to exceed boundary flux conditions, therefore triggering severe fouling, that leads to economic unfeasibility of the process in long terms

    An efficient flamelet progress-variable method for modeling non-premixed flames in weak electric fields

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    Combustion stabilization and enhancement of the flammability limits are mandatory objectives to improve nowadays combustion chambers. At this purpose, the use of an electric field in the flame region provides a solution which is, at the same time, easy to implement and effective to modify the flame structure. The present work describes an efficient flamelet progress-variable approach developed to model the fluid dynamics of flames immersed in an electric field. The main feature of this model is that it can use complex ionization mechanisms without increasing the computational cost of the simulation. The model is based on the assumption that the combustion process is not directly influenced by the electric field and has been tested using two chemi-ionization mechanisms of different complexity in order to examine its behavior with and without the presence of heavy anions in the mixture. Using a one- and two-dimensional numerical test cases, the present approach has been able to reproduce all the major aspects encountered when a flame is subject to an imposed electric field and the main effects of the different chemical mechanisms. Moreover, the proposed model is shown to produce a large reduction in the computational cost, being able to shorten the time needed to perform a simulation up to 40 times.Comment: 26 pages, 13 figures, paper accepted for publication on Computers and Fluid

    Chromium recovery by membranes for process reuse in the tannery industry

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    Leather tanning is a wide common industry all over the world. In leather processing, water is one of the most important medium, almost 40-45 L water kg-1 raw-hide or skin is used by tanneries for processing finished leathers. The composition of tannery wastewater presents considerable dissimilarities in the concentration range of pollutants both of inorganic (chlorides, with concentration ranging from several hundred to over 10,000 mg L-1 Cl–; sulphate (VI), ammonium ions and sulphide ions, exhibiting concentration that ranges from tens to several hundred mg L-1) and organic (the COD value is usually several thousand mg L-1 O2). Throughout the years, many conventional processes have been carried out to treat wastewater from tannery industry: unfortunately, in this case, biological treatment methods give rise to an excessive production of sludge, whereas physical and chemical methods are too expensive in terms of energy and reagent costs. In this work, a membrane process based on NF membrane modules was adopted to treat the tannery feedstock after primary conventional treatment. In a first step, the determination of all boundary flux parameters, in order to inhibit severe fouling formation during operation, were performed. After this, experimental work was carried out to validate the approach. The target of water purification was reached, that is the legal discharge to municipal sewer system in Italy of 90% of the initial wastewater stream volume. This allows having an immediate cost saving of 21%. Moreover, the developed process leads to a second benefit, that is the production of 5% of the initial volume as a highly chromium-rich concentrate at no cost suitable to tannery process recycle and reuse. In this case, cost saving rates exceeds 40%. At the end, scale-up of the investigated process will be discussed from technical and economic point of view

    Information-flux approach to multiple-spin dynamics

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    We introduce and formalize the concept of information flux in a many-body register as the influence that the dynamics of a specific element receive from any other element of the register. By quantifying the information flux in a protocol, we can design the most appropriate initial state of the system and, noticeably, the distribution of coupling strengths among the parts of the register itself. The intuitive nature of this tool and its flexibility, which allow for easily manageable numerical approaches when analytic expressions are not straightforward, are greatly useful in interacting many-body systems such as quantum spin chains. We illustrate the use of this concept in quantum cloning and quantum state transfer and we also sketch its extension to non-unitary dynamics.Comment: 7 pages, 4 figures, RevTeX

    Cannabinoids in the treatment of epilepsy: current status and future prospects

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    Cannabidiol (CBD) is one of the prominent phytocannabinoids found in Cannabis sativa, differentiating from Δ9-tetrahydrocannabinol (THC) for its non-intoxicating profile and its antianxiety/antipsychotic effects. CBD is a multi-target drug whose anti-convulsant properties are supposed to be independent of endocannabinoid receptor CB1 and might be related to several underlying mechanisms, such as antagonism on the orphan GPR55 receptor, regulation of adenosine tone, activation of 5HT1A receptors and modulation of calcium intracellular levels. CBD is a lipophilic compound with low oral bioavailability (6%) due to poor intestinal absorption and high first-pass metabolism. Its exposure parameters are greatly influenced by feeding status (ie, high fatcontaining meals). It is mainly metabolized by cytochrome P 450 (CYP) 3A4 and 2C19, which it strongly inhibits. A proprietary formulation of highly purified, plant-derived CBD has been recently licensed as an adjunctive treatment for Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS), while it is being currently investigated in tuberous sclerosis complex. The regulatory agencies’ approval was granted based on four pivotal double-blind, placebocontrolled, randomized clinical trials (RCTs) on overall 154 DS patients and 396 LGS ones, receiving CBD 10 or 20 mg/kg/day BID as active treatment. The primary endpoint (reduction in monthly seizure frequency) was met by both CBD doses. Most patients reported adverse events (AEs), generally from mild to moderate and transient, which mainly consisted of somnolence, sedation, decreased appetite, diarrhea and elevation in aminotransferase levels, the last being documented only in subjects on concomitant valproate therapy. The interaction between CBD and clobazam, likely due to CYP2C19 inhibition, might contribute to some AEs, especially somnolence, but also to CBD clinical effectiveness. Cannabidivarin (CBDV), the propyl analogue of CBD, showed anti-convulsant properties in pre-clinical studies, but a plant-derived, purified proprietary formulation of CBDV recently failed the Phase II RCT in patients with uncontrolled focal seizures

    Synthesis and application of zeolite and glass fiber supported zero valent iron nanoparticles as membrane component for removal nitrate and Cr (+6) ions

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    In the present paper the synthesis and characterization of zeolite and glass fiber supported zero valent iron nanoparticles (Ze-ZVI, GF-ZVI NPs) are reported.ZVI, Ze-ZVI and GF-ZVI NPs size, composition and morphology were characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Energy Dispersive Spectroscopy (EDS). Synthesized nanostructures were tested as reducing agents of nitrate and hexavalent Chromium. Batch experiments were carried for revealing of efficacy of prepared nanomaterials (ZE-ZVI NPs and GF-ZVI NPs). Nitrate removal efficiency (at initial concentration 50 mg/mL) was rapidly increased from 26% to 76% for GF-ZVI NPs at 60-240 min time interval for and from 34% to 90% for ZE-ZVI NPs at the same time interval.Also was studied the efficacy of prepared nanostructures ZE-ZVI and ZE-ZVI NPs as membrane component with 5% of ZVI NPS weight contentfor the removal of nitrate from water solution that made 85% for ZE-ZVI NPs and 76% for GF-ZVI NPs, respectively. The results of this study indicate that the application of GF-ZVI and ZE-ZVI NPs as membrane component is advantageous because it allows to prevent the additional pollution of treated solution caused by unreacted ZVI NPs

    Three–way compositional data: a multi–stage trilinear decomposition algorithm

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    The CANDECOMP/PARAFAC model is an extension of bilinear PCA and has been designed to model three-way data by preserving their multidimensional configuration. The Alternating Least Squares (ALS) procedure is the preferred estimating algorithm for this model because it guarantees stable results. It can, however, be slow at converging and sensitive to collinearity and over-factoring. Dealing with these issues is even more pressing when data are compositional and thus collinear by definition. In this talk the solution proposed is based on a multistage approach. Here parameters are optimized with procedures that work better for collinearity and over-factoring, namely ATLD and SWATLD, and then results are refined with ALS
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