Exponential series without denominators

For a commutative algebra which comes from a Zinbiel algebra the exponential series can be written without denominators. When lifted to dendriform algebras this new series satisfies a functional equation analogous to the Baker-Campbell-Hausdorff formula. We make it explicit by showing that the obstruction series is the sum of the brace products. In the multilinear case we show that the role the Eulerian idempotent is played by the iterated pre-Lie product.Comment: 13

Optical and plasmonic properties of twisted bilayer graphene: Impact of interlayer tunneling asymmetry and ground-state charge inhomogeneity

We present a theoretical study of the local optical conductivity, plasmon spectra, and thermoelectric properties of twisted bilayer graphene (TBG) at different filling factors and twist angles $\theta$. Our calculations are based on the electronic band structures obtained from a continuum model that has two tunable parameters, $u_0$ and $u_1$, which parametrize the intra-sublattice inter-layer and inter-sublattice inter-layer tunneling rate, respectively. In this Article we focus on two key aspects: i) we study the dependence of our results on the value of $u_0$, exploring the whole range $0\leq u_0\leq u_1$; ii) we take into account effects arising from the intrinsic charge density inhomogeneity present in TBG, by calculating the band structures within the self-consistent Hartree approximation. At zero filling factor, i.e. at the charge neutrality point, the optical conductivity is quite sensitive to the value of $u_0$ and twist angle, whereas the charge inhomogeneity brings about only modest corrections. On the other hand, away from zero filling, static screening dominates and the optical conductivity is appreciably affected by the charge inhomogeneity, the largest effects being seen on the intra-band contribution to it. These findings are also reflected by the plasmonic spectra. We compare our results with existing ones in the literature, where effects i) and ii) above have not been studied systematically. As natural byproducts of our calculations, we obtain the Drude weight and Seebeck coefficient. The former displays an enhanced particle-hole asymmetry stemming from the inhomogeneous ground-state charge distribution. The latter is shown to display a broad sign-changing feature even at low temperatures ($\approx 5~{\rm K}$) due to the reduced slope of the bands, as compared to those of single-layer graphene.Comment: 28 pages, 16 figures, 6 appendice

Determination of cadmium (II) and zinc (II) in olive oils by derivative potentiometric stripping analysis

A method for the determination of cadmium (II) and zinc (II) in olive oils by derivative potentiometric stripping analysis after dry ashing of the sample is described. The metal ions were concentrated as their amalgams on a glassy carbon working electrode that was previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally converted into dt dE 121, and E was plotted vs. dt dE 121, thus increasing sensitivity of the method and improving resolution of the analysis. Quantitative analysis was carried out by the method of standard additions; a good linearity was obtained in the range of concentrations examined. Recoveries of 92\u2013102% for cadmium (II) and of 89\u201399% for zinc (II) were obtained from an olive oil spiked at different levels. The detection limits were 5.1 ng g 121 for cadmium (II) and 7.6 ng g 121 for zinc (II)

Novel insights into cochlear information processing

Already Helmholtz profoundly addressed the question how the nonlinearity of the human hearing sensor, the cochlea, might shape human sound perception. At his time, research was, however, obstructed by the lack of experimental data regarding the amplification properties of the inner ear. In the meantime, accurate measuring methods have permitted the comparison of models of the hearing sensor with empirical data, leading to a strong revival of the interest into Helmholtz’s original research questions. In our paper, we describe some recent theoretical and modeling advances in the understanding of the nature of human pitch perception. We reveal a number of to date unexplained human auditory percept effects to be direct consequences of the nonlinear properties of the mammalian hearing sensor. Our insights also demonstrate, as a by-note, the limitations of the present reverse engineering approach towards cochlear implants

BIOMASS EXPLOITATION FOR ENERGY SUPPLY AND QUALITY COMPOST PRODUCTION. AN EXEMPLARY CASE OF CIRCULAR ECONOMY IN THE NORTH EAST OF ITALY

The goal 12 of the 2030 Agenda for Sustainable Development takes into consideration the responsible consumption and production in the perspective of circular economy. The agri-food sector is more actively involved in these initiatives, because it offers the possibility to exploit waste and by-products, by adopting suitable biotechnologies. Such processes can be carried out either under aerobic conditions, for the production of compost, or anaerobically, for the production of biogas. In this work the case of a plant managed by Desag Ecologia, located in the municipality of Sedegliano, in the North-East of Italy, is presented. The plant started up in June 2016. Its main activity consists in exploitation of the organic fraction of municipal solid waste and urban forestry green waste coming from separate waste collection. The basin of provenance of collected materials consists not only of the province of Udine, but also of other areas of the Friuli Venezia Giulia region and other northern Italian regions. The plant ensures the production of both biogas (used in a cogeneration installation for producing electricity and heat) and quality compost, which can be used in agriculture, after submission to physico-chemical analyses to verify the end-of-waste status. In this way, the reduction of waste disposal in landfill is ensured. Thermal energy is partially recovered for the production of hot water to heat the anaerobic digester, the leachate collection tank and the plant rooms. Approximately 10% of electricity is self-consumed for the needs of the anaerobic facility, the remaining amount is fed straight into the public electricity network

Determination of cadmium (II) and lead (II) in whole and skim milk by stripping chronopotentiometric analysis

A method for the determination of cadmium (II) and lead (II) in whole and skim milk by stripping chronopotentiometric analysis is described. The metal ions were concentrated as their amalgams on a glassy carbon working electrode that was previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally converted into dt dE-1, and E was plotted vs. dt dE-1, thus increasing both sensitivity of the method and resolution of the analysis. Quantitative analysis was carried out by the method of standard additions. A good linearity was obtained in the range of concentrations examined. Recoveries of 94-100% for cadmium (II) and of 91-98% for lead (II) were obtained from a sample spiked at different levels. The detection limits were 4.4 ng g-1 for cadmium (II) and 8.6 ng g-1 for lead (II) and the relative standard deviations (mean of nine determinations) were 4.1 and 5.6%, respectively. Results obtained on commercial whole and skim milk were not significantly different from those obtained by inductively coupled plasma atomic emission spectrometry

High performance liquid chromatographic determination of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in processes citrus juices

The occurrence of 2-furaldehyde (F) and 5-hydroxymethyl-2-furaldehyde (HMF) in processed citrus juices is an indication of quality deterioration. A close relationship between flavor changes and F content exists, while HMF can give rise to browning reactions. Both F and HMF are formed during heat processing or storage at improper temperatures. The detection of these compounds becomes more and more important as aseptic processing and packaging of citrus juices are becoming widespread. Aseptic packaging allows higher temperatures during distribution and storage to be employed without microbial spoilage, but off-flavors develop as citrus products are exposed to these conditions. In this paper a method of determination by high performance liquid chromatography (HPLC) is described. The method is based on the formation of the 2,4-dinitrophenylhydrazones of carbonyl compounds and subsequent reversed-phase separation of these derivatives. Derivatization is carried out by utilizing an acidic solution of 2,4-dinitrophenylhydrazine in acetonitrile. Precipitation of the derivatives of carbonyl compounds is thus avoided, and direct injection of the sample into the HPLC system is allowed. The determination offers a high specificity and a detection limit of the order of 10-8 mol/l for both analytes. Recoveries from an orange juice spiked at different levels are quantitative. Reproducibility data are presented

Determination of zinc (II), cadmium (II), lead (II) and copper (II) in common and balsamic vinegar by stripping chronopotentiometry

A method for the determination of zinc (II), cadmium (II), lead (II) and copper (II) in common and balsamic vinegar by stripping chronopotentiometry is described. The metal ions were concentrated as their amalgams on a glassy carbon working electrode that was previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally converted into dt dE-1, and E was plotted vs. dt dE-1, thus increasing both sensitivity of the method and resolution of the analysis. Quantitative analysis was carried out by the method of standard additions. A good linearity was obtained in the range of concentrations examined. Recoveries of 90-98% for zinc (II), 91- 97% for cadmium (II), 94-98% for lead (II) and 93-97% for copper (II) were obtained from a sample spiked at different levels. The detection limits were 10.6 ng g-1 for zinc (II), 2.2 ng g-1 for cadmium (II), 3.4 ng g-1 for lead (II) and 4.2 ng g-1 for copper (II) and the relative standard deviations (mean of nine determinations) were 4.8, 6.5, 3.2 and 5.3%, respectively. Results obtained on commercial common and balsamic vinegars were not significantly different from those obtained by atomic absorption spectrometr