Theory and applications of the Vlasov equation

Forty articles have been recently published in EPJD as contributions to the topical issue "Theory and applications of the Vlasov equation". The aim of this topical issue was to provide a forum for the presentation of a broad variety of scientific results involving the Vlasov equation. In this editorial, after some introductory notes, a brief account is given of the main points addressed in these papers and of the perspectives they open.Comment: Editoria

Efficient Statistical Extraction of the Per-Unit-Length Capacitance and Inductance Matrices of Cables with Random Parameters

Cable bundles often exhibit random parameter variations due to uncertain or uncontrollable physical properties and wire positioning. Efficient tools, based on the so-called polynomial chaos, exist to rapidly assess the impact of such variations on the per-unit-length capacitance and inductance matrices, and on the pertinent cable response. Nevertheless, the state-of-the-art method for the statistical extraction of the per-unit-length capacitance and inductance matrices of cables suffers from several inefficiencies that hinder its applicability to large problems, in terms of number of random parameters and/or conductors. This paper presents an improved methodology that overcomes the aforementioned limitations by exploiting a recently-published, alternative approach to generate the pertinent polynomial chaos system of equations. A sparse and decoupled system is obtained that provides remarkable benefits in terms of speed, memory consumption and problem size that can be dealt with. The technique is thoroughly validated through the statistical analysis of two canonical structures, i.e. a ribbon cable and a shielded cable with random geometry and position

Comparison of Stochastic Methods for the Variability Assessment of Technology Parameters

This paper provides and compares two alternative solutions for the simulation of cables and interconnects with the inclusion of the effects of parameter uncertainties, namely the Polynomial Chaos (PC) method and the Response Surface Modeling (RSM). The problem formulation applies to the telegraphers equations with stochastic coefficients. According to PC, the solution requires an expansion of the unknown parameters in terms of orthogonal polynomials of random variables. On the contrary, RSM is based on a least-square polynomial fitting of the system response. The proposed methods offer accuracy and improved efficiency in computing the parameter variability effects on system responses with respect to the conventional Monte Carlo approach. These approaches are validated by means of the application to the stochastic analysis of a commercial multiconductor flat cable. This analysis allows us to highlight the respective advantages and disadvantages of the presented method

Intestinal parasites of owned dogs and cats from metropolitan and micropolitan areas: prevalence, zoonotic risks, and pet owner awareness in northern Italy

Intestinal parasites of dogs and cats are cosmopolitan pathogens with zoonotic potential for humans. Our investigation considered their diffusion in dogs and cats from northern Italy areas, specifically the metropolitan area of Milan and two micropolitan areas of neighboring provinces. It included the study of the level of awareness in pet owners of the zoonotic potential from these parasites. A total of 409 fresh fecal samples were collected from household dogs and cats for copromicroscopic analysis and detection of Giardia duodenalis coproantigens. The assemblages of Giardia were also identified. A questionnaire about intestinal parasites biology and zoonotic potential was submitted to 185 pet owners. The overall prevalence of intestinal parasites resulted higher in cats (47.37%-60.42%) and dogs (57.41%-43.02%) from micropolitan areas than that from the metropolis of Milan (dogs: P = 28.16%; cats: P = 32.58 %). The zoonotic parasites infecting pets under investigation were T. canis and T. cati, T. vulpis, Ancylostomatidae, and G. duodenalis assemblage A. Only 49.19% of pet owners showed to be aware of the risks for human health from canine and feline intestinal parasites. Parasitological results in pets and awareness determination in their owners clearly highlight how the role of veterinarians is important in indicating correct and widespread behaviors to reduce risks of infection for pets and humans in urban areas

Efficient Statistical Extraction of the Per-Unit-Length Capacitance and Inductance Matrices of Cables with Random Parameters

Cable bundles often exhibit random parameter variations due to uncertain or uncontrollable physical properties and wire positioning. Efficient tools, based on the so-called polynomial chaos, exist to rapidly assess the impact of such variations on the per-unit-length capacitance and inductance matrices, and on the pertinent cable response. Nevertheless, the state-of-the-art method for the statistical extraction of the per-unit-length capacitance and inductance matrices of cables suffers from several inefficiencies that hinder its applicability to large problems, in terms of number of random parameters and/or conductors. This paper presents an improved methodology that overcomes the aforementioned limitations by exploiting a recently-published, alternative approach to generate the pertinent polynomial chaos system of equations. A sparse and decoupled system is obtained that provides remarkable benefits in terms of speed, memory consumption and problem size that can be dealt with. The technique is thoroughly validated through the statistical analysis of two canonical structures, i.e. a ribbon cable and a shielded cable with random geometry and position

Linear Polyamidoamines as Novel Biocompatible Intumescent Flame Retardants for Cotton

Since the middle of the last century, many industrial and academic researchers have devoted a lot of effort to the development of safe and effective flame- retardants (FR). As regards cotton, phosphorylated compounds were the predominant FR for several decades [1] despite many of them had been shown to be bioaccumulative.[1] Recently, biomolecules including proteins have been proposed as FR.[2] Many linear polyamidoamines (PAAs), a family of synthetic polymers with exceptional structural versatility,[3] have high thermal stability coupled with chain structure and side substituents reminding those of proteins.[4] These features suggested that PAAs could act as FR. This presentation reports on the results obtained with a library of eight PAAs applied as coatings on cotton fabrics from aqueous solutions. All tested PAAs warrant remarkable potential as surface-confined intumescent FR. In ignitability tests, six of them exposed to direct flame for 10 s do not burn, but produce carbonaceous crusts sheltering the underneath sample. Thermogravimetric analyses show that at T 65 400 \ub0C all PAAs leave in air substantial char residues that oxidize at T > 500 \ub0C. At 450 \ub0C they form porous carbonaceous structures indicating the tendency to intumesce. In horizontal flame spread tests, cotton stripes impregnated with most PAAs extinguish flame at add-ons ranging from 4 to 20%, whereas untreated cotton vigorously burns without leaving residues. Upon 35 kW/m2 heat flux, all PAA-treated samples significantly reduce the main combustion parameters. References [1] R. A. Horrocks, Polym. Degrad. Stab. 2011, 96, 377. [2] L. Costes, F. Laoutid, S. Brohez, P. Dubois, Mater. Sci. Eng. Report, R. 2017, 117, 1. [3] P. Ferruti, J. Polym. Sci, Part A: Polym. Chem. 2013, 51, 2319. [4] F. Danusso, P. Ferruti, Polymer 1970, 11, 88

Nonlinear structures: explosive, soliton and shock in a quantum electron-positron-ion magnetoplasma

Theoretical and numerical studies are performed for the nonlinear structures (explosive, solitons and shock) in quantum electron-positron-ion magnetoplasmas. For this purpose, the reductive perturbation method is employed to the quantum hydrodynamical equations and the Poisson equation, obtaining extended quantum Zakharov-Kuznetsov equation. The latter has been solved using the generalized expansion method to obtain a set of analytical solutions, which reflect the possibility of the propagation of various nonlinear structures. The relevance of the present investigation to the white dwarfs is highlighted.Comment: 7 figure

Chiral recognition in D-, L-arginine derived polyamidoamino acids and sodium deoxycholate solutions

Nowadays the spontaneous self-organization of a polymer into an ordered structure is a sought-after property of many smart materials, whose applications might range from catalysis1 to drug-delivery2. However, literature regarding the role played by these specific conformations in chiral recognition remains scarce. In this context, polyamidoamino acids (PAACs) are an emerging class of stimuli-responsive bioinspired synthetic polymers able to self-assemble into pH depend conformations.3,4 Arginine based PAACs, named ARGO7, were obtained in water at pH 8-9 from the stepwise polyaddition of L- or D-arginine to N,N\u2019methylenebisacrylamide. Results indicated Mn 8500, PDI 1.4 and Rh of 1.2 nm.3 Molecular dynamics (MD) and circular dichroism (CD) showed ARGO7 folded into a rigid structure, reminiscent of the hairpin conformation, solely driven by the polymer main chain. Due to its ability to self-assemble in solution forming chiral structures, L- and D-ARGO7 may selectively interact with biological components. To assess chiral recognition, sodium deoxycholate (NaDC), one of the components of bile salts, was chosen as a chiral model surface. In aqueous solution, NaDC showed three different pH dependent behaviour: homogeneous solution (pH>8), gel phase (pH 7-8) and aggregation/flocculation (pH<6.5). Notwithstanding the ability of NaDC to self-assemble into different conformations at each pH interval, signs of chiral recognition were found in NaDC gel phase only. Conformational modifications were probed by circular dichroism spectroscopy: both D- and L-ARGO7 changed shape and magnitude of the CD pattern, whereas D,LARGO7 did not modify the CD spectra of NaDC. After 8 days, NaDC compact structure loosened, ended up being fluid and the CD pattern were completely modified due to NaDC and D- or L-ARGO7 interactions. Incoming SANS studies will probably highlight the mechanisms and dynamics of the chiral interactions in these polyelectrolyte-micelle systems. (1) Luo, R.; Zhu, M.; Shen, X.; Li, S. J. Catal. 2015, 331, 49. (2) Qui\uf1ones, J. P.; Peniche, H.; Peniche, C. Polymers. 2018, 10, 3, 235. (3) Manfredi, A.; Mauro, N.; Terenzi, A.; Alongi, J.; Lazzari, F.; Ganazzoli, F.; Raffaini, G.; Ranucci, E.; Ferruti, P. ACS Macro Lett. 2017, 6, 987. (4) Lazzari, F.; Manfredi, A.; Alongi, J.; Mendichi, R.; Ganazzoli, F.; Raffaini, G.; Ferruti, P.; Ranucci, E. Polymers 2018, 10, 1261

Probing chiral interactions between L- and D-arginine-based polymers and sodium deoxycholate solutions

Nowadays the spontaneous self-organization of a polymer into an ordered structure is a soughtafter property of many smart materials, whose applications might range from catalysis [1] to drugdelivery [2]. However, literature regarding the role played by these specific conformations in chiral recognition remains scarce. In this context, polyamidoamino acids (PAACs) are an emerging class of stimuli-responsive bioinspired synthetic polymers able to self-assemble into pH depend conformations [3,4]. PAACs are an off-spring of polyamidoamines (PAAs), a family of polymers obtained by the Michael-type polyaddition of prim-monoamines or sec-diamines with bisacrylamides. The reaction occurs in aqueous solution at pH = 8\u20139 and at room temperature. By using \u3b1-amino acids as monomers, PAACs are obtained. The first example of PAAC was named ARGO7, obtained by the stepwise polyaddition in water of L- or D-arginine to N,N\u2019-methylenebisacrylamide. Results indicated Mn 8500, PDI 1.4 and Rh of 1.2 nm [3]. Molecular dynamics (MD) and circular dichroism (CD) showed ARGO7 folded into a rigid structure, reminiscent of the hairpin conformation, solely driven by the polymer main chain. Due to its ability to self-assemble in solution forming chiral structures, L- and D-ARGO7 may selectively interact with biological components. To assess chiral recognition, sodium deoxycholate (NaDC), one of the components of bile salts, was chosen as a chiral model surface. In aqueous solution, NaDC showed three different pH dependent behaviour: homogeneous solution (pH>8), gel phase (pH 7-8) and aggregation/flocculation (pH<6.5). Notwithstanding the ability of NaDC to self-assemble into different conformations at each pH interval, signs of chiral recognition were found in NaDC gel phase only. Conformational modifications were probed by circular dichroism spectroscopy: both D- and L-ARGO7 changed shape and magnitude of the CD pattern, whereas D,L-ARGO7 did not modify the CD spectra of NaDC. After 8 days, NaDC compact structure loosened, ended up being fluid and the CD pattern were completely modified due to NaDC and D- or L-ARGO7 interactions. Incoming diffusion NMR and SANS studies will probably highlight the mechanisms and dynamics of the chiral interactions in these polyelectrolyte-micelle systems. [1] Luo, R.; Zhu, M.; Shen, X.; Li, S. J. Catal. 2015, 331, 49. [2] Qui\uf1ones, J. P.; Peniche, H.; Peniche, C. Polymers. 2018, 10, 3, 235. [3] Manfredi, A.; Mauro, N.; Terenzi, A.; Alongi, J.; Lazzari, F.; Ganazzoli, F.; Raffaini, G.; Ranucci, E.; Ferruti, P. ACS Macro Lett. 2017, 6, 987. [4] Lazzari, F.; Manfredi, A.; Alongi, J.; Mendichi, R.; Ganazzoli, F.; Raffaini, G.; Ferruti, P.; Ranucci, E. Polymers 2018, 10, 1261

Two-Body Random Ensembles: From Nuclear Spectra to Random Polynomials

The two-body random ensemble (TBRE) for a many-body bosonic theory is mapped to a problem of random polynomials on the unit interval. In this way one can understand the predominance of 0+ ground states, and analytic expressions can be derived for distributions of lowest eigenvalues, energy gaps, density of states and so forth. Recently studied nuclear spectroscopic properties are addressed.Comment: 8 pages, 4 figures. To appear in Physical Review Letter