We investigate the dynamics of a phase-separating binary fluid, containing colloidal dumbbells anchored to the fluid-fluid interface. Extensive lattice Boltzmann-immersed boundary method simulations reveal that the presence of soft dumbbells can significantly affect the curvature dynamics of the interface between phase-separating fluids, even though the coarsening dynamics is left nearly unchanged. In addition, our results show that the curvature dynamics exhibits distinct non-local effects, which might be exploited for the design of new soft mesoscale materials. We point out that the inspection of the statistical dynamics of the curvature can disclose new insights into local inhomogeneities of the binary fluid configuration, as a function of the volume fraction and aspect ratio of the dumbbells.

We discuss the state of art of Lattice Boltzmann (LB) computing, with special focus on prospective LB schemes capable of meeting the forthcoming Exascale challenge. After reviewing the basic notions of LB computing, we discuss current techniques to improve the performance of LB codes on parallel machines and illustrate selected leading-edge applications in the Petascale range. Finally, we put forward a few ideas on how to improve the communication/computation overlap in current largescale LB simulations, as well as possible strategies towards fault-tolerant LB schemes. (C) 2019 Published by Elsevier Ltd.

Fully three-dimensional, time-dependent, direct simulations of the non-ideal Navier-Stokes equations for a two-component fluid shed light into the mechanism which inhibits droplet breakup in step emulsifiers below a critical threshold of the width-to-height (w/h) ratio of the microfluidic nozzle. Below w/h similar to 2.6, the simulations provide evidence of a smooth topological transition of the fluid from the confined rectangular channel geometry to an isotropic (spherical) expansion of the fluid downstream the nozzle step. Above such threshold, the transition from the inner to the outer space involves a series of dynamical rearrangements which keep the free surface in mechanical balance. Such rearrangements also induce a backflow of the ambient fluid which, in turn, leads to jet pinching and ultimately to its rupture, namely, droplet formation. The simulations show remarkable agreement with the experimental value of the threshold, which is found around w/h similar to 2.56. Published under license by AIP Publishing.

This article is part of the theme issue 'Multiscale modelling, simulation and computing: from the desktop to the exascale'. We outline the main ideas behind the numerical modelling of soft flowing crystals, paying special attention to their application to microfluidic devices for the design of novel mesoscale porous materials.

alpha-quartz is one of the most important SiO2 polymorphs because it is the basis of very common minerals, especially for seabed materials with geoscientific importance. The elastic characterization of these materials is particularly relevant when the properties governing phonon and sound propagation are involved. These studies are especially interesting for oil exploration purposes. Recently, we published a new method that constitutes to the best of our knowledge the first attempt to recreate longitudinal and transversal perturbations in a simulation box to observe their propagation through the crystal by means of a set of descriptors [D. Melgar et al., J. Phys. Chem. C 122, 3006-3013 (2018)]. The agreement with the experimental S- and P-wave velocities was rather excellent. Thus, an effort has been undertaken to deepen the particularities of this new methodology. Here, bearing in mind this encouraging initial methodology-development progress, we deepen our knowledge of the particularities of this new methodology in presenting a systematic investigation of the implementation of the perturbation source. This includes new ways of creating the perturbation, as well as analyzing the possible effects the perturbation amplitude could have on the resultant velocities. In addition, different force fields were tested to describe the interatomic interactions. The lack of dependence of the seismic velocities on the way the perturbation is created and the perturbation amplitude, and the good agreement with the experimental results are the main reasons that allow the definition of this new methodology as robust and reliable. These qualities are consolidated by the physical behavior of the calculated velocities in the presence of vacancies and under stress. The development of this method opens up a new line of research of calculating seismic velocities for geophysically relevant materials in a systematic way, with full control not only on the sample features (composition, porosity, vacancies, stress, etc.) but also on the particularities of perturbation itself, as well as determining optimal system-response metrics. Published under license by AIP Publishing.

Computer simulations of bi-continuous two-phase fluids with interspersed dumbbells show that, unlike rigid colloids, soft dumbbells do not lead to arrested coarsening. However, they significantly alter the curvature dynamics of the fluid-fluid interface, whose probability density distributions are shown to exhibit (i) a universal spontaneous transition (observed even in the absence of colloids) from an initial broad-shape distribution towards a highly localized one and (ii) super-diffusive dynamics with long-range effects. Both features may prove useful for the design of novel families of soft porous materials.

We present a mesoscale representation of near-contact interactions between colliding droplets which permits one to reach up to the scale of full microfluidic devices, where such droplets are produced. The method is demonstrated for the case of colliding droplets and the formation of soft flowing crystals in flow-focusing microfluidic devices. This model may open up the possibility of multiscale simulation of microfluidic devices for the production of new droplet and bubble-based mesoscale porous materials.

We present a mesoscale kinetic model for multicomponent flows, augmented with a short range forcing term, aimed at describing the combined effect of surface tension and near-contact interactions operating at the fluid interface level. Such a mesoscale approach is shown to (i) accurately capture the complex dynamics of bouncing colliding droplets for different values of the main governing parameters, (ii) predict quantitatively the effective viscosity of dense emulsions in micro-channels and (iii) simulate the formation of the so-called soft flowing crystals in microfluidic focusers.

The dynamic interaction of complex fluid interfaces is highly sensitive to near-contact interactions occurring at the scale of ten of nanometers. Such interactions are difficult to analyze because they couple self-consistently to the dynamic morphology of the evolving interface, as well as to the hydrodynamics of the interstitial fluid film. In this work, we show that, above a given magnitude threshold, near-contact interactions trigger nontrivial microvorticity patterns, which in turn affect the effective near-contact interactions, giving rise to persistent fluctuating ripples at the fluid interface. In such a regime, near-contact interactions may significantly affect the macroscopic arrangement of emulsion configurations, such as those arising in soft-flowing microfluidic crystals.

Given methane hydrates' importance in marine sediments, as well as the widespread use of seabed acoustic-signaling methods in oil and gas exploration, the elastic characterization of these materials is particularly relevant. A greater understanding of the properties governing phonon, sound, and acoustic propagation would help to better classify methane-hydrate deposits, aiding in their discovery. Recently, we have published a new nonequilibrium molecular-dynamics (NEMD) methodology to recreate longitudinal and transverse perturbations, observing their propagation through a crystalline lattice by various metrics, to study the underlying S- and P-wave velocities (achieving excellent agreement with experiment) [Melgar et al., J. Phys. Chem. 122(5), 3006-3013 (2018); ibid. 150, 084101 (2019)]. Here, we apply these NEMD methods to methane-clathrate systems to study acoustic-propagation characteristics, as well as the lattice elastic behavior. In so doing, we determine S- and P-wave velocities in excellent accord with experiment; we also ascertain the allowable magnitude range of acoustic perturbation and establish a threshold for lattice breakup and hydrate decomposition. Interestingly, upon dissociation, we observe the formation of methane nanobubbles, which agrees with previous studies on the microscopic fundamentals of hydrate dissociation by various means.

The crack density within a fault's damage zone is thought to vary as seismic rupture is approached, as well as in the postseismic period. Moreover, external stress loads, seasonal or tidal, may also change the crack density in rocks, and all such processes can leave detectable signatures on seismic attenuation. Here we show that attenuation time histories from the San Andreas Fault at Parkfield are affected by seasonal loading cycles, as well as by 1.5-3-year periodic variations of creep rates, consistent with Turner et al. (2015, https://biblioproxy.cnr.it:2481/10.1002/2015JB011998), who documented a broad spectral peak, between 1.5 and 4 years, of the spectra calculated over the activity of repeating earthquakes, and over InSAR time series. After the Parkfield main shock, we see a clear modulation between seismic attenuation correlated to tidal forces. Opposite attenuation trends are seen on the two sides of the fault up to the M6.5 2003 San Simeon earthquake, when attenuation changed discontinuously, in the same directions of the relative trends. Attenuation increased steadily of over one year on the SW side of the San Andreas Fault, until the San Simeon earthquake, whereas it decreased steadily on the NE side of the San Andreas Fault, roughly for the six months prior to the event. Random fluctuations are observed up to the 2004 M6 Parkfield main shock, when rebounds in opposite directions are observed, in which attenuation decreased on the SW side, and increased on the NE side.

We study nonnegative solutions of the Cauchy problem

The deep relationships, already existing since the 8th century BC, with Etruscan and Greek culture have triggered in the indigenous communities of Apulia and Basilicata a series of socio-cultural dynamics that will lead to a fundamental stage of social differentiation, based no longer on the role but on the high rank. If in the previous centuries the warrior was characterized only by the presence of the bronze spear, from the end of the 9th and especially in the 8th century the element that distinguishes it is the sword, which becomes a symbol of personal prestige. In this phase, the armed people is often accompanied by instruments connected with specialized activities (chisels) or with agriculture (agricultural tools), which also express the control of the means of production and the new concept of land ownership. In very rare cases, in the funerary assemblages there are some prestige goods imported from Etruria or from Cumae, such as bronze basins, lebetes and cauldrons, connected with ceremonial practices of Euboic- Tyrrhenian influence. By the 7th century BC, when the so-called phenomenon of the "birth of the princes" is affirmed, the traditional warlike ideology of the indigenous aristocracy does not seem to undergo deep changes. The high rank of the warrior continues to be highlighted by the sword, but also by the spear and shield. However, the assemblages are enriched with numerous prestige goods that circulate along the routes that connect Basilicata and Apulia to the Etruscan Campania, especially bronze vases and other valuable objects, bearers of a new aristocratic cultural model. A different framework is offered by the tombs of warriors related to the 6th century BC, which present more articulated assemblages, in which are found many prestige goods from the Etruscan and Hellenic world, such as bronze vases and figured pottery, while the panoply is enriched with Corinthian helmets, greaves and shields with figured girders (schildband) according to the customs of the Greek hoplites. It is above all a parade armament that serves to emphasize the rank and the high social level of the deceased. Another data is given by the presence of the chariot that characterizes not only the male tombs, but also the female ones of the dominant classes. If, on the one hand, it is proposed as an instrument of war, on the other it constitutes a further sign of social distinction. The use of the horse is attested by the presence in some exceptional burials of very precious parade harnesses that protect the chest and the muzzle, often characterized by a refined figured decoration. The ceremonial and symbolic use of these elements of the panoply, as well as of figured girders of shields and swords, are emphasized by the ornamental and figured themes, but also by the presence of Black-Figure Attic pottery with mythical episodes and war scenes or gender representations through which the heroic world of the prince is expressed. Towards the end of the 6th century BC and in the subsequent one there was a substantial continuity with the warlike ideology of the Archaic period, even if the armament no longer constitutes the main element of attention for the ruling classes, now replaced by convivial practices. In some cases, figured Attic pottery and weapons constitute a complex system of images with references to the reality of combat (we can think to the labours of Heracles or the duels of Achilles), which constitute precise symbols of self-representation and recall the heroic condition of the deceased.

The first carved ambers appear in the Adriatic area at the end of the eighth century BC with the beginning of the Orientalizing period. Among the most active centers, the Etruscan Verucchio is one of the main poles for the sorting of amber. At the beginning of the sixth century, a fundamental role is exercised from Piceno and the Etruscan Felsina, whose intercept part of the tra!cs previously directed on the Adriatic road. Real amber sculptures of high stylistic level appear towards the second half of the sixth century, found in the rich italic tombs (Basilicata, Apulia, Piceno), traced back to two specialized workshops, localizable in Canosa and Armento, at whose birth they certainly contributed artisans from Ionia and from Etruria.

The discoveries of the last thirty years in Apulia have highlighted the leading role of this region, and especially ancient Peucetia, in the evolution of Lucanian and Apulian red-figured pottery. In fact, from the last decades of the fifth century BC onwards the aristocratic classes of Apulia (in the fourth century also those of the Daunian district) were the main patrons and consumers of the products of Italic workshops. As the most complex elements of the funerary assemblage there was a specific demand for those objects. They were entrusted with the ideological messages and representative needs of the deceased, displaying their wealth, the social role they played in life, and their adoption of cultural and ideological models of Hellenic origin. They also refer to the deceased's forms of religiosity and to their adherence to and participation in beliefs of 'salvific type', albeit filtered through their own cultural values and ideologies. In fact, it is highly likely that the needs of such a rarefied patronage influenced Italic figured production from the beginning their specific requests governed the selection of themes and compositions.

We obtain sharp decay estimates in time in the context of Sobolev spaces for smooth solutions to the one-dimensional Jin Xin model under the diffusion scaling, which are uniform with respect to the singular parameter of the scaling. This provides the convergence to the limit nonlinear parabolic equation both for large time and for the vanishing singular parameter. The analysis is performed by means of two main ingredients. First, a crucial change of variables highlights the dissipative property of the Jin Xin system and allows us to observe a faster decay of the dissipative variable with respect to the conservative one, which is essential in order to close the estimates. Next, the analysis relies on a deep investigation of the Green function of the linearized Jin Xin model, depending on the singular parameter, combined with the Duhamel formula in order to handle the nonlinear terms.

We consider the Schrödinger operator -?+V for negative potentials V, on open sets with positive first eigenvalue of the Dirichlet-Laplacian. We show that the spectrum of -?+V is positive, provided that V is greater than a negative multiple of the logarithmic gradient of the solution to the Lane-Emden equation -?u=u (for some 1<=q<2). In this case, the ground state energy of -?+V is greater than the first eigenvalue of the Dirichlet-Laplacian, up to an explicit multiplicative factor. This is achieved by means of suitable Hardy-type inequalities, that we prove in this paper.

Given a bounded open set in [Formula presented], [Formula presented], and a sequence [Formula presented] of compact sets converging to an [Formula presented]-dimensional manifold [Formula presented], we study the asymptotic behaviour of the solutions to some minimum problems for integral functionals on [Formula presented], with Neumann boundary conditions on [Formula presented]. We prove that the limit of these solutions is a minimiser of the same functional on [Formula presented] subjected to a transmission condition on [Formula presented], which can be expressed through a measure [Formula presented] supported on [Formula presented]. The class of all measures that can be obtained in this way is characterised, and the link between the measure [Formula presented] and the sequence [Formula presented] is expressed by means of suitable local minimum problems.

We systematically investigate the role of different swimming patterns on the concentration distribution of bacterial suspensions confined between two flat walls, by considering wild-type motility Escherichia coli and Pseudomonas aeruginosa, which perform Run and Tumble and Run and Reverse patterns, respectively. The experiments count motile bacteria at different distances from the bottom wall. In agreement with previous studies, an accumulation of motile bacteria close to the walls is observed. Different wall separations, ranging from 100 to 250?m, are tested. The concentration profiles result to be independent on the motility pattern and on the walls' separation. These results are confirmed by numerical simulations, based on a collection of self-propelled dumbbells-like particles interacting only through steric interactions. The good agreement with the simulations suggests that the behavior of the investigated bacterial suspensions is determined mainly by steric collisions and self-propulsion, as well as hydrodynamic interactions.

This book constitutes the refereed proceedings of the 9th International Conference on Computational Logistics, ICCL 2018, held in Vietri sul Mare, Italy, in October 2018. The 32 full papers presented were carefully reviewed and selected from 71 submissions. They are organized in topical sections as follows: maritime shipping and routing, container handling and container terminals, vehicle routing and multi-modal transportation, network design and scheduling, logistics oriented combinatorial optimization.