11,384 research outputs found
Estimation of the gravitational wave polarizations from a non template search
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
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
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
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
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
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
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
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
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
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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