Combed 3-Manifolds with Concave Boundary, Framed Links, and Pseudo-Legendrian Links

We provide combinatorial realizations, according to the usual objects/moves scheme, of the following three topological categories: (1) pairs (M,v) where M is a 3-manifold (up to diffeomorphism) and v is a (non-singular vector) field, up to homotopy; here possibly the boundary of M is non-empty and v may be tangent to the boundary, but only in a concave fashion, and homotopy should preserve tangency type; (2) framed links L in M, up to framed isotopy; (3) triples (M,v,L), with (M,v) as above and L transversal to v, up to pseudo-Legendrian isotopy (transversality-preserving simultaneous homotopy of v and isotopy of L). All realizations are based on the notion of branched standard spine, and build on results previously obtained. Links are encoded by means of diagrams on branched spines, where the diagram is smooth with respect to the branching. Several motivations for being interested in combinatorial realizations of the topological categories considered in this paper are given in the introduction. The encoding of links is suitable for the comparison of the framed and the pseudo-Legendrian categories, and some applications are given in connection with contact structures, torsion and finite-order invariants. An estension of Trace's notion of winding number of a knot diagram is introduced and discussed.Comment: 38 pages, 33 figure

Ion acceleration by radiation pressure in thin and thick targets

Abstract Radiation Pressure Acceleration (RPA) by circularly polarized laser pulses is emerging as a promising way to obtain efficient acceleration of ions. We briefly review theoretical work on the topic, aiming at characterizing suitable experimental scenarios. We discuss the two reference cases of RPA, namely the thick target ("Hole Boring") and the (ultra)thin target ("Light Sail") regimes. The different scaling laws of the two regimes, the related experimental challenges and their suitability for foreseen applications are discussed

Effect of citric acid on browning of fresh-cut potatoes and on texture after frying

Fresh-cut potato (Solanum tuberosum L.) is a product widely consumed, but the susceptibility of this tube.r to browning is a drawback and limiting factor for its shelf life. This study aimed to evaluate the predisposition of different potato cultivars for being minimally processed, the effect of citric acid in inhibiting browning and the quality of the fried potato during the product shelf-life.Postprint (updated version

Time series analysis of Coulomb collisions in a beam dynamics simulation

Abstract In this paper, a time series analysis of collisional effects in a numerical simulation of a coasting beam transverse dynamics is presented. The simulation performs a numerical integration of the Hamilton's equations of a two-dimensional system of particles, describing the transverse dynamics of the beam. Then, an analysis of the time series generated has been applied in order to describe the dynamics of the system by means of the mean field equations, with the addition of a stochastic process in order to model Coulomb collisions

Spin structures on 3-manifolds via arbitrary triangulations

Let M be an oriented compact 3-manifold and let T be a (loose) triangulation of M, with ideal vertices at the components of the boundary of M and possibly internal vertices. We show that any spin structure s on M can be encoded by extra combinatorial structures on T. We then analyze how to change these extra structures on T, and T itself, without changing s, thereby getting a combinatorial realization, in the usual "objects/moves" sense, of the set of all pairs (M,s). Our moves have a local nature, except one, that has a global flavour but is explicitly described anyway. We also provide an alternative approach where the global move is replaced by simultaneous local ones.Comment: 49 pages, many figure

A First approach of using ultrasound as an alternative for blanching in vacuum-packaged potato strips

The effect of ultrasound (US) (40 kHz, 200 W, 3 min), blanching (85 °C, 3.5 min), and the combination of both methods was evaluated on the quality of vacuum-packaged potato strips stored at 3 ± 1 °C for up to 10 days. For this study, two cultivars of potatoes were assessed. For blanched Agata samples, the lightness (L*) decreased over 12 % (p < 0.05). Moreover, their hue increased up to 100, obtaining lesser yellow potato strips. In contrast, US did not affect the hue values. The losses of firmness of blanched potato strips were notable (35 % for Agata and 51 % for Agria), whereas US did not change this property (p < 0.05). Nevertheless, no significant differences were found in the total starch content at 10 days. Agata and Agria showed different metabolic behaviors of sucrose in the refrigerated storage. Therefore, Agria cultivar retained better color after frying. These results suggest that US had less impact on color and improve the firmness in vacuum-packaged potato strips with no added chemicals.Postprint (author's final draft

Branched Spines of 3-Manifolds and Reidemeister Torsion of Euler Structures

We consider homotopy classes of non-singular vector fields on three-manifolds with boundary and we define for these classes torsion invariants of Reidemeister type. We show that torsion is well-defined and equivariant under the action of the appropriate homology group using an elementary and self-contained technique. Namely, we use the theory of branched standard spines to express the difference between two homotopy classes as a combination of well-understood elementary catastrophes. As a special case we are able to reproduce Turaev’s theory of Reidemeister torsion for Euler structures on closed manifolds of dimension three

Seismic history from in situ 36Cl cosmogenic nuclide data on limestone fault scarps using Bayesian reversible jump Markov chain Monte Carlo

International audienceConstraining the past seismic activity and the slip-rates of faults over several millennials is crucial for seismic hazard assessment. Chlorine 36 (36 Cl) in situ produced cosmogenic nuclide is increasingly used to retrieve past earthquakes histories on seismically exhumed limestone normal fault-scarps. Following Schlagenhauf et al., (2010) modelling approach, we present a new methodology to retrieve the exhumation history based on a Bayesian transdimensional inversion of the 36 Cl data. This procedure uses the reversible jump Markov chains Monte-Carlo algorithm (RJ-MCMC, Green 1995) which enables 1-exploring the parameter space (number of events, age and slip of the events), 2-finding the most probable scenarios, and 3- precisely quantifying the associated uncertainties. Through a series of synthetic tests, the algorithm revealed a great capacity to constrain event slips and ages in a short computational time (several days) with a precision that can reach 0.1 ky and 0.5 m for the age and slip ofexhumation event, respectively. In addition, our study show that the amount of 36 Cl accumulated when the sampled fault-plane was still buried under the colluvial wedge, prior its exhumation, might represents up to 35 % of the total 36 Cl. This contribution can be accurately 25 determined with a depth profile that strongly increases the precision of the exhumation scenario

The Process of Digitalization of the Urban Environment for the Development of Sustainable and Circular Cities: A Case Study of Bologna, Italy

The residential heritage that was built during the great expansion of real estate after the Second World War has severe deficiencies in structural safety, fire resistance, energy efficiency, and accessibility and these cannot be solved with sustainable renovation measures. This study focuses on replacement interventions and promotes a management model that addresses three areas (technical, social, and economic) and it refers to the application of the circularity principle to the construction sector for the goal of climate neutrality by 2050. The final objective is to define a protocol—namely, the guidelines—to reference in a decision-making process that promotes urban regeneration by comparing demolition with reconstruction and renovation. The proposed methodology allows for the determination of suitable areas in Bologna for replacement and the joining of the municipal geodatabase with data from archival research on building permits in 1949–1965 by using GIS software. This digital archive can be implemented in a digital twin for an urban block, which can become a predictive tool for urban planning and the management of the whole life of a building. The main result is the characterization of urban blocks by identifying typical features belonging to specific building libraries that are validated with density analyses. These urban clusters and building archetypes can be used to assess targeted intervention measures by using specific tools, such as predictive maps and 3D city models