620 research outputs found
A Unique Multi-Messenger Signal of QCD Axion Dark Matter
We propose a multi-messenger probe of QCD axion Dark Matter based on
observations of black hole-neutron star binary inspirals. It is suggested that
a dense Dark Matter spike may grow around intermediate mass black holes
(). The presence of such a spike produces
two unique effects: a distinct phase shift in the gravitational wave strain
during the inspiral and an enhancement of the radio emission due to the
resonant axion-photon conversion occurring in the neutron star magnetosphere
throughout the inspiral and merger. Remarkably, the observation of the
gravitational wave signal can be used to infer the Dark Matter density and,
consequently, to predict the radio emission. We study the projected reach of
the LISA interferometer and next-generation radio telescopes such as the Square
Kilometre Array. Given a sufficiently nearby system, such observations will
potentially allow for the detection of QCD axion Dark Matter in the mass range
to .Comment: 5 pages, 3 figures. Appendix added with additional figures. Updated
to published versio
Adsorption of phenol/tyrosol from aqueous solutions on macro-reticular aromatic and macro-porous polystyrene cross-linked with divinylbenzene polymeric resins
The current work aims at separating by adsorption of low-molecular-weight organic compounds in a
nanofiltration concentrate of the olive mill wastewaters. The experimental investigations on adsorption of
phenol/tyrosol in single and binary systems were conducted in batch mode by using the commercially
available macroporous resins FPX66 and MN202. The structures of such resins were examined by FTIR
before and after adsorption. The operating parameters affecting the adsorption process such as resin dosage,
contact time, pH, and initial concentration of phenol/tyrosol were investigated. Fast phenol and tyrosol uptakes
were observed for both resins. It can be attributed to their physical properties, for instance high specific area
and microporous area. The adsorption selectivity of phenol is larger than tyrosol when using FPX66 resin, but
smaller if MN202 resin is used. Acidic pH appeared to be always favourable for the adsorption. A synergetic
effect between solutes was observed since adsorption of phenol and tyrosol in the binary systems was faster
than the individual sorption of each solute. Five isotherms namely Langmuir, Freundlich, DubininRadushkevich,
Temkin and Redlich-Peterson were selected to fit the obtained equilibrium experimental data.
Finally, desorption of the examined compounds with ethanol (EtOH) allowed a maximum around 85 % of
phenol, and equal to 94 % of tyrosol on FPX66 and MN202 resins
Adsorption of phenol/tyrosol from aqueous solutions on macro-reticular aromatic and macro-porous polystyrene cross-linked with divinylbenzene polymeric resins
The current work aims at separating by adsorption of low-molecular-weight organic compounds in a
nanofiltration concentrate of the olive mill wastewaters. The experimental investigations on adsorption of
phenol/tyrosol in single and binary systems were conducted in batch mode by using the commercially
available macroporous resins FPX66 and MN202. The structures of such resins were examined by FTIR
before and after adsorption. The operating parameters affecting the adsorption process such as resin dosage,
contact time, pH, and initial concentration of phenol/tyrosol were investigated. Fast phenol and tyrosol uptakes
were observed for both resins. It can be attributed to their physical properties, for instance high specific area
and microporous area. The adsorption selectivity of phenol is larger than tyrosol when using FPX66 resin, but
smaller if MN202 resin is used. Acidic pH appeared to be always favourable for the adsorption. A synergetic
effect between solutes was observed since adsorption of phenol and tyrosol in the binary systems was faster
than the individual sorption of each solute. Five isotherms namely Langmuir, Freundlich, DubininRadushkevich,
Temkin and Redlich-Peterson were selected to fit the obtained equilibrium experimental data.
Finally, desorption of the examined compounds with ethanol (EtOH) allowed a maximum around 85 % of
phenol, and equal to 94 % of tyrosol on FPX66 and MN202 resins
Diclofenac sorption from synthetic water: Kinetic and thermodynamic analysis
This work investigated diclofenac sorption on 0.5g L-1 activated carbon in a range of temperature (288-318K) and of initial sorbate concentration (24-218mgL-1). Thermodynamic modelling was carried out with the Langmuir isotherm. For kinetic modelling we compared the so-called Diffusion-Controlled Langmuir Kinetics (DCLK) and the pseudo-second order (PSO) model. The maximum sorption capacity of the sorbent, equal to 180mgg-1, was independent of temperature. Experimental data fitted well with both kinetic models, yet the DCLK model was found to be more informative about the mechanism of the process. Kinetic parameters (α, β) increased with the temperature, with α value rising from 5×10-5 to 20×10-5 L mg-1min-0.5, and β value rising from 3×10-6 to 20×10-6 L mg-1min-1 in the temperature range investigated
Protein polymorphisms and coagulation properties of Cilentana goat milk
The study was carried out on 86 ‘Cilentana’ goats, distributed in four herds. Milk samples were collected during morning and evening milking, and pH, dry matter, fat, protein and lactose percentage as well as the lactodynamometric profile were detected to determine enzymatic phase duration, coagulation speed and curd consistency. Polymorphism of the s1-casein protein was detected. Four alleles (designated A, B, E and F) and nine genotypes were detected. The association of these nine genotypes with chemical composition and lactodynamometric characteristics was investigated. The BF genotype was the most frequent (35.5 %), followed by EE (15.1 %) and AF and BB (10.4%). The F allele showed the highest frequency and it negatively influenced cheesemaking as it was associated with a low s1-casein content. Goats with the AB genotype produced milk with higher dry matter, protein and fat content compared with the FF genotype. Moreover, milk from the AB genotype has a lower enzymatic phase duration and a higher coagulation speed than the BB genotype. Curd consistency is higher for milk from the AA genotype, when compared with the EF genotype. All the chemical and lactodynamometric characteristics varied with herd and months of control; furthermore, the milk obtained from morning milking showed better coagulation properties
Geopolymer composites for potential applications in cultural heritage
A new class of geopolymer composites, as materials alternative to traditional binders, was synthesized and its potentialities as restoration material in Cultural Heritage has been explored. This material has been prepared through a co-reticulation reaction in mild conditions of a metakaolin-based geopolymer inorganic matrix and a commercial epoxy resin. The freshly prepared slurry displays a consistency, workability and thixotropic behavior that make it suitable to be spread on different substrates in restoration, repair and reinforcement actions, even on walls and ceilings. Applicability and compatibility tests on tuff and concrete substrates were carried out and the microstructure of the samples in correspondence of the transition zone was analyzed by means of scanning electron microscope (SEM) observations and energy dispersive spectroscopy (EDS) mapping. Our studies pointed out the formation of a continuous phase between the geopolymer composite and tuff and concrete substrates, highlighting a high compatibility of the geopolymer binder with different kinds of materials. These features indicate a large potential for applications of these materials in Cultural Heritage
Investigation of dark count rate in NbRe microstrips for single photon detection
Superconducting microstrip single photon detectors (SMSPDs) received great interest since they are expected to combine the excellent performance of superconducting nanostrip single photon detectors with the possibility to cover large active areas using low-cost fabrication techniques. In this work, we fabricated SMSPDs based on NbRe to investigate the role of vortices in the dark counts events in this innovative material and in devices with micrometer size. We realized devices with different layouts, namely single microstrips and pairs of parallel microstrips. The energy barriers related to the motion of single vortices or vortex-antivortex pairs, responsible of detection events, have been determined and compared with the ones of similar devices based on different materials, such as MoSi, WSi and NbN. The analysis confirms the high potential of NbRe for the realization of superconducting single photon detectors with large areas
Antarctic Special Protected Area 161 as a Reference to Assess the Effects of Anthropogenic and Natural Impacts on Meiobenthic Assemblages
The Antarctic region is usually considered a pristine area. Nevertheless, regional warming
effects and increasing human activities, including the presence of several research stations, are
inducing considerable environmental changes that may affect the ecosystem’s functions. Therefore,
during the XXXIII Antarctic expedition, we carried out an investigation in Terra Nova bay (Ross
Sea), close to the Antarctic Specially Protected Area (ASPA) n.161. In particular, we compared the
effects of two different types of impacts on the meiobenthic assemblages: anthropogenic impact
(AI), associated with the activity of Mario Zucchelli Research Station (MZS), and natural impact
(NI) attributable to a large colony of Adélie penguins (Pygoscelis adeliae) in Adelie Cove. For each
impacted site, a respective control site and two sampling depths (20 and 50 m) were selected. Several
environmental variables (pH, dissolved oxygen, major and minor ions, heavy metals, organic load,
and sediment grain size) were measured and analysed, to allow a comprehensive characterization
of the sampling areas. According to the criteria defined by Unites States Environmental Protection
Agency (US EPA 2009), heavy metal concentrations did not reveal critical conditions. However,
both the MZS (AI20) and penguin colony (NI20) sites showed higher heavy metal concentrations,
the former due to human activities related to the Italian research station, with the latter caused by
the penguins excrements. Meiobenthic richness and abundance values suggested that the worst
ecological condition was consistently related to the Adélie penguins colony. Furthermore, the higher
contribution of r-strategists corroborates the hypothesis that the chronic impact of the penguin
colonies may have stronger effects on the meiobenthos than the human activities at the MZS. Food
is not limited in shallow Antarctic bottoms, and microscale differences in primary and secondary
production processes can likely explain the greater spatial heterogeneity, highlighted both by the
univariate and multivariate attributes of meiobenthic assemblage (i.e., richness, diversity, abundance,
whole structure assemblage, and rare taxa) at the deeper stations. As reported in other geographical
regions, the assemblage structure of rare meiobenthic taxa is confirmed to be more susceptible to
environmental variations, rather than the whole assemblage structure
[2-Butyl-4-(4-tert-butylbenzyl)-1,2,4-triazol-3-ylidene]chlorido[(1,2,5,6-η)-cycloocta-1,5-diene]iridium(I)
In the title compound, [IrCl(C8H12)(C17H25N3)], the IrI ion has a distorted square-planar coordination geometry. The N-heterocyclic carbene ligand has an extended S-shaped conformation. The butyl group was refined using a two-part 1:1 disorder model. In the crystal, three unique weak C—H⋯Cl contacts are present. Two of these form a motif described as R
2
1(6) in graph-set notation, while a third forms an R
2
2(8) motif about a crystallographic inversion center. The result is a chain structure which extends parallel to the crystallographic a axis
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