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Jet substructure in heavy-ion collisions is a rapidly evolving area with lots of intriguing new measurements. This contribution presents a selection of recent jet-substructure measurements from experiments at the LHC, in particular, soft-drop groomed radii of jets and reclustered large-radius jets from ATLAS, jet axis difference and generalized jet angularities from ALICE, as well as dijet shapes and b-jet shapes from the CMS experiment.

The submesh allocation problem is to recognize and locate a free submesh that can accommodate a request for a submesh of a specified size. An efficient submesh allocation strategy is required for achieving high performance on mesh multicomputers. In this paper, we propose a new best fit submesh allocation strategy. The proposed strategy maintains and uses a free submesh list to get global information for free submeshes. For an allocation request, the strategy tries to allocate a best fit submesh which causes the least amount of potential fragmentation so as to preserve the large free submeshes to be as many as possible and to prevent processor fragmentation for later requests. For this purpose, we introduce a novel function for quantifying the degree of potential fragmentation of submeshes. The proposed strategy has the complete submesh recognition capability. Extensive simulation is carried out to compare it with the previous strategies, and experimental results indicate that it exhibits the best performance along with an about 30% average improvement over the previous best strategy.

Melting and fragmentation behaviors of Ni₄₂₉ cluster have been studied with molecular-dynamics simulations using a size-dependent empirical model potential energy function. To monitor thermal behaviors of the cluster, we calculated some physical quantities such as average potential energy per atom, specific heat, radial atomic distribution, bond length distribution, average interatomic distance, nearest neighbor distance and average coordination number as a function of temperature. The roles of the surface and core atoms in the melting and fragmentation process of the cluster are also investigated by considering the surface and the bulk coordination numbers of the cluster.

We perform extensive molecular dynamics simulations to study the mass size distribution of a two-dimensional fragmentation process. Our model consists of a large number of particles interacting through the Lennard–Jones potential. The fragmentation is induced by suddenly imposing a radial component on the particles' velocities, in order to mimic an explosion phenomenon. We then investigate the effect of the input energy on the resulting mass distribution of fragments.

Time evolution of number of cities, population of cities, world population, and size distribution of present languages are studied in terms of a new model, where population of each city increases by a random rate and decreases by a random division. World population and size distribution of languages come out in good agreement with the available empirical data.

A study of the distribution of the value of traded goods under the Harmonized System is presented. The ramifications of this classification system are found to exhibit an approximate power law decay, indicating complexity and self-organization in the nomenclature of traded merchandises. For almost all countries with available data, log-values of annually imported and exported goods are well described by three-parameter Weibull distributions. This distribution commonly appears in particles size distributions, suggesting a connection between random fragmentation processes and the mechanisms behind the international trade of merchandises. Analysis of the resulting values for the fitting parameters from 1995 to 2018 shows a nearly constant linear relationship between the parameters of the Weibull distributions, so that, for each country, the distribution of log-values can be approximately characterized by a single shape parameter $\beta$. The empirical findings of this paper suggest that specialization on trading a constant set of goods prevents the values of all traded merchandises from growing/decreasing simultaneously.

This paper describes a two-dimensional computer simulation of solid fracture that allows the body and the fragments to be followed well beyond the point of simple crack formation. The model is based on discrete particle computer simulations used for studying granular flows. Here, macroscopic polygonal solid are constructed by “gluing” together small elements. Depending on the stress conditions the glued bonds between the elements can respond elastically, undergo plastic failure or break, allowing cracks to propagate across the macroscopic particle along the boundaries between their microscopic constituents. In essence, this process creates a simulated material upon which breakage occurs. Several element shapes have been studied.

This paper uses the model described in Ref. 1 to simulate fracture in many simple systems with the goal of evaluating the advantages and deficiencies of the model. The examples include compressive failure of a rectangular sample, four-point shear failure of a beam and the impact of particles with a plate and binary impacts of particles. Where possible, the simulated results seem to be in good agreement with typical experimental results. Finally, a simulation of ball-milling, which involves the flow and fracture of many particles is shown to demonstrate the overall utility of the model.

This paper describes an extension to a computer simulation of solid fracture. In the original model, rigid elements are assembled into a simulated solid by "gluing" the elements together with compliant boundaries which fracture when the tensile strength of the glued joints is exceeded. The current extension applies portions of the finite element technique to allow changes in the shapes of elements. This is implemented at the element level and no global stiffness matrix is assembled; instead, the elements interact across the same compliant boundaries used in the rigid element simulation. As a result, the simulated material can conform to any desired shape and thus can handle large elastic and plastic deformation. This model is intended to study the propagation of multitudinous cracks through simulated solids to aid the understanding of problems such as the impact-induced fragmentation of particles.

This paper describes an extension into three dimensions of an existing two-dimensional technique for simulating brittle solid fracture. The fracture occurs on a simulated solid created by "gluing" together space-filling polyhedral elements with compliant interelement joints. Such a material can be shown to have well-defined elastic properties. However, the "glue" can only support a specified tensile stress and breaks when that stress is exceeded. In this manner, a crack can propagate across the simulated material. A comparison with experiment shows that the simulation can accurately reproduce the size distributions for all fragments with linear dimensions greater than three element sizes.

We study the phenomena associated with the low-velocity impact of two solid discs of equal size using a cell model of brittle solids. The fragment ejection exhibits a jet-like structure the direction of which depends on the impact parameter. We obtain the velocity and the mass distribution of the debris. Varying the radius and the initial velocity of the colliding particles, the velocity components of the fragments show anomalous scaling. The mass distribution follows a power law in the region of intermediate masses.

The scaling law of Edwards et al., for cluster fragmentation of critical percolation clusters is not confirmed by analogous Monte Carlo simulations at the Curie point of the two-dimensional Ising model.

Globalization has its detractors as well as supporters. Concerns have been expressed about the greater ease of fragmenting the production process so that more parts can be outsourced to a variety of countries. Highly developed regions worry about the possibility of greater unemployment or lower unskilled wage rates. Less developed regions are concerned that they may not possess a comparative advantage in the service link activities that promote fragmentation. The paper discusses these issues, with special emphasis on India and China.

This paper is a non-technical survey of the literature on offshoring and outsourcing, with special focus on the relevance of this literature for Asia. We first see how and to what extent this new literature helps us understand firms' tradeoffs between outsourcing and integration, the variation in the mixes of organizational forms and the location of outsourced activities. We also explore what plausibly triggers offshoring and thereafter what determines its dynamics. Finally, we draw inferences from the existing theory and empirical work about the developmental impact of offshoring on Asia, with special attention to issues related to inequality and poverty.

A salient feature of the East Asian region is the persistent discrepancy between the progress in de facto and de jure economic integration. East Asia has long been said to be the champion of loose regional economic integration, with deepening intra-regional trade and investment linkages in the absence of any formal cooperative scheme. However, an oft-heard claim is that East Asia has been shifting recently towards an institution-based form of regional economic cooperation, primarily as a result of the 1997–98 financial crisis. Next to post-crisis financial cooperative schemes under the ASEAN+3, the surge of Regional Trade Agreements (RTAs) involving East Asian countries is thought by some to further substantiate this claim. The objective of the paper is twofold; first, to assess the validity of the aforementioned claim; and second, to examine the links between de facto and de jure economic integration in East Asia compared to other regions of the world. In the process, the sequencing between trade and monetary cooperation is also addressed. The paper starts by providing a candid assessment of the current state of play of economic cooperation in East Asia (de jure integration), both from the trade and the financial/monetary perspective, and highlights the limitations of the formal regional integration movement in East Asia to date. As a next step, it explores the changing nature of intra-regional trade and investment linkages, contrasts it to the situation in other parts of the world such as Europe and examines to what extent this new form of interdependence may be instrumental in making formal regional economic schemes more attractive. A major conclusion is that de facto trade integration may not automatically lead to deeper regional trade cooperation de jure and that its impact is likely to be stronger on monetary cooperation projects.

This paper examines the trade of machinery parts and components between Thailand and the other Mekong countries though gravity model, for the purpose of assessing the existing production networks in Mekong region by applying fragmentation theory. The findings are: First, the evolution of production networks between Thailand and Vietnam was identified in terms of their two-way trade integration. Second, the trade intensity between Thailand and Vietnam was explained by the fragmentation factors, i.e., their gaps in per capita GDP and the relatively lower service-link costs in Vietnam. Third, the trade less-integration of Thailand with Cambodia and Myanmar was explained by their higher service-link costs.

Recent LHCb measurements of the $J/\psi$ meson production in jets are analyzed using fragmentation jet function formalism. It is shown that disagreement with theoretical predictions for distribution over the fraction of $J/\psi$ transverse momentum $z(J/\psi )$ in the cases of prompt production can be explained if one takes into account evolution of the fragmentation function and contributions from double parton scattering (DPS) mechanism or gluon fragmentation.

This work deals with the decay analysis of three compound nuclei ${}^{77}{\mathrm{\text{As}}}^{\ast }$, ${}^{83}{\mathrm{\text{Br}}}^{\ast }$ and ${}^{86}{\mathrm{\text{Sr}}}^{\ast }$ formed in proton-induced reactions $\mathrm{\text{p}}+{}^{76}\mathrm{\text{Ge}}$, $\mathrm{\text{p}}+{}^{82}\mathrm{\text{Se}}$ and $\mathrm{\text{p}}+{}^{85}\mathrm{\text{Rb}}$ at incident beam energies of 1–5 MeV using the Dynamical Cluster-decay Model (DCM). The motive is to explore the decay of compound systems formed via light charged particles as projectiles. The experimentally available data of n-evaporation for the aforementioned systems are addressed by optimizing the neck-length parameter $\mathrm{\Delta }R$, using spherical fragmentation approach. The comparative analysis of the decay structure of the chosen systems is carried out at a common incident beam energy $E_{\mathrm{\text{beam}}}\sim 3.6$ MeV. The effect of angular momentum $(\ell )$ and quadrupole $({\beta }_2)$-deformations is explored in reference to the decay structure/fragmentation of compound systems. In addition to this, the sensitivity of DCM-based cross-sections toward level density parameter (LDP) $a$ is also analyzed. The relative role of mass-dependent level density parameter $a(A)$ is also investigated for compound systems belonging to light and heavy mass region. Lastly, a theoretical systematics is explored where the proton beam in the reaction $\mathrm{\text{p}}+{}^{76}\mathrm{\text{Ge}}$ is replaced by a neutron beam forming the compound system ${}^{77}{\mathrm{\text{Ge}}}^{\ast }$, having the same $A$, but $Z$ one less than that of the compound system formed in the reaction using proton beam, and its effect on the decay characteristics such as preformation probability, penetration probability and barrier height is analyzed.

We present the results on fragmentation differences of quark and gluon jets obtained by CDF at . We compare the multiplicities and momentum distributions of charged particles in two data samples: dijet data and photon+jet data. These two samples have a different quark/gluon jet content, which allows a measurement of the inclusive properties of gluon and quark jets. The results are compared to the earlier measurements obtained at e+e- collisions and to the re-summed perturbative QCD calculations.

The fragmentation functions of D⁰, D^±, , D*^o, D*^± and at are measured with a data set of 102.7 fb^-1. Fragmentation model parametrizations (Peterson, Kartvelishvili, Collins-Spiller, Lund, and Bowler models) are compared to the data. The data at high x≃1 indicate a contribution of non-perturbative QCD processes.