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Scalar Field Dark Matter (SFDM) comprised of ultralight ($\gtrsim 10^{-22}$ eV) bosons is an alternative to standard, collisionless Cold Dark Matter (CDM) that is CDM-like on large scales but inhibits small-scale structure formation. As a Bose-Einstein condensate, its free-field ("fuzzy") limit (FDM) suppresses structure below the de Broglie wavelength, $\lambda_\text{deB}$, creating virialized haloes with central cores of radius $\sim\lambda_\text{deB}$, surrounded by CDM-like envelopes, and a halo mass function (HMF) with a sharp cut-off on small scales. With a strong enough repulsive self-interaction (SI), structure is inhibited, instead, below the Thomas-Fermi (TF) radius, $R_\text{TF}$ (the size of an SI-pressure-supported ($n=1$)-polytrope), when $R_\text{TF} > \lambda_\text{deB}$. Previously, we developed tools to describe SFDM dynamics on scales above $\lambda_\text{deB}$ and showed that SFDM-TF haloes formed by Jeans-unstable collapse from non-cosmological initial conditions have $R_\text{TF}$-sized cores, surrounded by CDM-like envelopes. Revisiting SFDM-TF in the cosmological context, we simulate halo formation by cosmological infall and collapse, and derive its transfer function from linear perturbation theory to produce cosmological initial conditions and predict statistical measures of structure formation, such as the HMF. Since FDM and SFDM-TF transfer functions both have small-scale cut-offs, we can align them to let observational constraints on FDM proxy for SFDM-TF, finding FDM with particle masses $1 \lesssim m/(10^{-22} \text{ eV}/c^2) \lesssim 30$ corresponds to SFDM-TF with $10 \gtrsim R_\text{TF}/(1 \text{ pc}) \gtrsim 1$, favoring sub-galactic (sub-kpc) core-size. The SFDM-TF HMF cuts off gradually, however, leaving more small-mass haloes: its Jeans mass shrinks so fast, scales filtered early can still recover and grow!, Comment: 30 pages, 10 figures, accepted by MNRAS 09/22/21, comments welcome

Using a set of $\Lambda$CDM simulations of cosmic structure formation, we study the evolving connectivity and changing topological structure of the cosmic web using state-of-the-art tools of multiscale topological data analysis (TDA). We follow the development of the cosmic web topology in terms of the evolution of Betti number curves and feature persistence diagrams of the three (topological) classes of structural features: matter concentrations, filaments and tunnels, and voids. The Betti curves specify the prominence of features as a function of density level, and their evolution with cosmic epoch reflects the changing network connections between these structural features. The persistence diagrams quantify the longevity and stability of topological features. In this study we establish, for the first time, the link between persistence diagrams, the features they show, and the gravitationally driven cosmic structure formation process. By following the diagrams' development over cosmic time, the link between the multiscale topology of the cosmic web and the hierarchical buildup of cosmic structure is established. The sharp apexes in the diagrams are intimately related to key transitions in the structure formation process. The apex in the matter concentration diagrams coincides with the density level at which, typically, they detach from the Hubble expansion and begin to collapse. At that level many individual islands merge to form the network of the cosmic web and a large number of filaments and tunnels emerge to establish its connecting bridges. The location trends of the apex possess a self-similar character that can be related to the cosmic web's hierarchical buildup. We find that persistence diagrams provide a significantly higher and more profound level of information on the structure formation process than more global summary statistics like Euler characteristic or Betti numbers., Comment: 23 pages, 14 figures, 1 table. Revised and shortened version, submitted to MNRAS

The influence of carbon nanotubes (CNTs) on the mechanical properties and structure formation during reactive sintering of B4C materials with Si addition was studied. Upon infiltrating the B4C structure with molten silicon, a non-porous composite was formed with a density of 2.45-2.55 g/cm3 and a hardness of 22-27 GPa. The formation of highly dispersed B-C-Si phases was observed in the interphase of adjacent B4C particles due to the incorporation of Si into B4C structures. These phases increase the bonding strength between B4C particles. In spite of the fact that the addition of 1-5 wt% Multi-Walled Carbon Nanotubes decreases the green density of the compacts, the flexural strength of the infiltrated material significantly increased. The improvement of the strength of ceramics modified with MWCNTs was interpreted in terms of the formation of thin flattened SiC crystals at the interfaces between B4C and B-C-Si particles, which strengthen the interfaces between ceramic particles.

Cosmological shock waves are ubiquitous to cosmic structure formation and evolution. As a consequence, they play a major role in the energy distribution and thermalization of the intergalactic medium (IGM). We analyze the Mach number distribution in the Dianoga simulations of galaxy clusters performed with the SPH code GADGET-3. The simulations include the effects of radiative cooling, star formation, metal enrichment, supernova and active galactic nuclei feedback. A grid-based shock-finding algorithm is applied in post-processing to the outputs of the simulations. This procedure allows us to explore in detail the distribution of shocked cells and their strengths as a function of cluster mass, redshift and baryonic physics. We also pay special attention to the connection between shock waves and the cool-core/non-cool core (CC/NCC) state and the global dynamical status of the simulated clusters. In terms of general shock statistics, we obtain a broad agreement with previous works, with weak (low-Mach number) shocks filling most of the volume and processing most of the total thermal energy flux. As a function of cluster mass, we find that massive clusters seem more efficient in thermalising the IGM and tend to show larger external accretion shocks than less massive systems. We do not find any relevant difference between CC and NCC clusters. However, we find a mild dependence of the radial distribution of the shock Mach number on the cluster dynamical state, with disturbed systems showing stronger shocks than regular ones throughout the cluster volume., Comment: 19 pages, 15 figures, accepted for publication in MNRAS

Introduction.The need for a more efficient and varied use of waste from the pulp and paper industry dictates the need to search for new directions for the use of such waste in construction materials science technologies.Materials and methods.In the studies the fibre waste of the Perm Cardboard LLC company with a moisture content after washing of 300% by weight was used. Currently, many issues of theory and practice the production of materials from the fibre waste are not entirely solved, resulting in a number of provisions borrowed from the theory of the production of concrete mineral aggregates, as well as the production of pulp and paper industry.Results.Due to its chemical and material composition, the possibility of using the fibre waste in construction materials science technologies as an independent air binder is shown. The studies have established that the initial moisture content of the fibre waste as a binder affects the final quality indicators of a dry material. Thus, the lowest dry material density of 350 kg/m3 is observed at the initial humidity of the mixture in the range of 650% by weight. At a density of 350 kg/m3, the hygroscopicity of the material is 4.3%, the shrinkage from 10 to 25%. The drying time of the product is within 11 hours. A leveling high shrinkage is achieved by introducing light aggregates with a rough surface during the molding process.Discussion and conclusions.The obtained data on the structure, the composition of the fibre waste, as well as the dependence and regularities of the behavior of a highly concentrated dispersed system of the ‘fibre waste-water’ type show the possibility of using the fibre waste for the production of thermal insulation materials, both as a main component and in a composition with aggregates as an independent air binder. At the same time, the final density indicators of thermal insulation products are within the limits established by regulatory documents.

The electrophysical characteristics of the PZT film formed on a silicon by the method of high-frequency reactive plasma sputtering were studied, and their relationship with the structure of the fil...

A dense HfC(Si, O)-HfB2(Si, O) composite was fabricated by reactive spark plasma sintering using HfC and SiB6 as starting reactants. The best ablation resistance was obtained with the composite fabricated with the addition of 15 vol.% SiB6. After ablation under an oxyacetylene flame for 60 s, the mass and linear ablation rates of this composite were −0.007 mg cm−2 s−1 and −0.233 μm s−1, respectively. The negative ablation rates are the result of a slight mass gain/thickness increase, which indicate that the oxidation process was stable and mechanical scouring was limited during ablation. This enhanced ablation resistance was attributed to a unique double-layered oxide formation, which possessed lower oxygen permeability and better mechanical strength. The solid solution nature of the composite and its appropriate phase composition were responsible for the stable oxide structure formation.

Structures that are periodic on a microscale in three dimensions are abundant in nature, for example, in the cellular arrays that make up living tissue. Such structures can also be engineered, appearing in smart materials1–4, photonic crystals5, chemical reactors6, and medical7 and biomimetic8 technologies. Here we report that fluid–fluid interfacial energy drives three-dimensional (3D) structure emergence in a micropillar scaffold. This finding offers a rapid and scalable way of transforming a simple pillar scaffold into an intricate 3D structure that is periodic on a microscale, comprising a solid microscaffold, a dispersed fluid and a continuous fluid. Structures generated with this technique exhibit a set of unique features, including a stationary internal liquid–liquid interface. Using this approach, we create structures with an internal liquid surface in a regime of interest for liquid–liquid catalysis. We also synthesize soft composites in solid, liquid and gas combinations that have previously not been shown, including actuator materials with temperature-tunable microscale pores. We further demonstrate the potential of this method for constructing 3D materials that mimic tissue with an unprecedented level of control, and for microencapsulating human cells at densities that address an unresolved challenge in cell therapy. The revelation that fluid–fluid interfacial energy can drive structure formation in micropillar scaffolds offers a scalable way of synthesizing soft composites, which may have applications in building materials that mimic biological tissue.

The review of the works on the fabrication-technology studies, patterns of structure formation, and properties of in situ composites is presented. The main advantage of in situ (natural) composites is the thermodynamic stability of their composition and the coherence (conjugation) of the lattices of the contacting phases. All these ones provide the composite with a high level of the physical and mechanical properties. As shown, composite materials of this type are formed in the process of directed phase transformations, such as eutectic crystallization, eutectoid decomposition, etc., caused by a temperature gradient, as well as a result of diffusional changes in composition. The conditions for the growth of in situ composites are formulated. The mechanisms of growth of composite structures of the eutectic type are considered. The factors influencing on the morphology of structures of the eutectic type are indicated. The considered technological methods make it possible to obtain materials with predetermined properties, in which the size, volumetric composition, and spatial arrangement of phases are characteristic of in situ composites. The paper provides a large number of examples of in situ composites: from low-melting Bi-based alloys to refractory eutectics based on Mo and W (Bi–MnBi, Cd–Zn, Al–Al3Ni, Al–Al4La, Al–Al10CaFe2, Al–Al9FeNi, Al–Al3Zr, Al–Al3Sc, Au–Co, Si–TaSi2, Cr–HfC, Cr–ZrC, Cr–NbC, Cr–NbC, Cr–TaC, Nb–Nb5Si3, Mo–ZrC, Mo–HfC, W–TiC, W–ZrC, W–HfC, etc.). Processes and aspects of structure formation are considered. The influence of additional doping on the structure and properties of composite materials of the eutectic type of binary systems, as well as the features of the structure formation of ternary colonies in the composite are considered.

The results of studies of the structure in the joint zone of stainless steel 50Cr15Мo2V with carbon steel 20 after explosion welding and subsequent heat treatment at a temperature of 1000 ° C and holding times of 5-20 hours are presented. The formation of a continuous diffusion layer in the joint zone is shown, the thickness of which depends on the holding time.

The article discusses the problems of ensuring high-quality formation and normative properties of butt joints of the 1560M and 1980T1 (AMg6 and B48) aluminum alloys as applied to engineering. A method is proposed for joining materials by means of EBW using an electron beam sweep. Homogeneous and dissimilar joints have been investigated, heat treatment of joint from the 1980T1 alloy and a dissimilar joint from the 1560M + 1980T1 alloys is recommended. The paper also presents the results of mechanical properties testing, the corrosion resistance and the delayed fracture tests. A welding technology that makes it possible to obtain high-quality butt-welded joints from aluminum alloys in thicknesses up to 40 mm has been developed and implemented.

Protoclusters, the progenitors of the most massive structures in the Universe, have been identified at redshifts of up to 6.6. Besides exploring early structure formation, searching for protoclusters at even higher redshifts is particularly useful to probe the reionization. Here we report the discovery of the protocluster LAGER-z7OD1 at a redshift of 6.93, when the Universe was only 770 million years old and could be experiencing rapid evolution of the neutral hydrogen fraction in the intergalactic medium. The protocluster is identified by an overdensity of 6 times the average galaxy density, and with 21 narrowband selected Lyman-$\alpha$ galaxies, among which 16 have been spectroscopically confirmed. At redshifts similar to or above this record, smaller protogroups with fewer members have been reported. LAGER-z7OD1 shows an elongated shape and consists of two subprotoclusters, which would have merged into one massive cluster with a present-day mass of $3.7 \times 10^{15}$ solar masses. The total volume of the ionized bubbles generated by its member galaxies is found to be comparable to the volume of the protocluster itself, indicating that we are witnessing the merging of the individual bubbles and that the intergalactic medium within the protocluster is almost fully ionized. LAGER-z7OD1 thus provides a unique natural laboratory to investigate the reionization process., Comment: 9 pages, 5 figures, and 1 table. Accepted by Nature Astronomy

To determine experimentally how the multiple folding pathways of a protein differ, in the order in which the structural parts are assembled, has been a long-standing challenge. To resolve whether structure formation during folding can progress in multiple ways, the complex folding landscape of monellin has been characterized, structurally and temporally, using the multisite time-resolved FRET methodology. After an initial heterogeneous polypeptide chain collapse, structure formation proceeds on parallel pathways. Kinetic analysis of the population evolution data across various protein segments provides a clear structural distinction between the parallel pathways. The analysis leads to a phenomenological model that describes how and when discrete segments acquire structure independently of each other in different subensembles of protein molecules. When averaged over all molecules, structure formation is seen to progress as α-helix formation, followed by core consolidation, then β-sheet formation, and last end-to-end distance compaction. Parts of the protein that are closer in the primary sequence acquire structure before parts separated by longer sequence.

The present article focuses on the basic physics of structure formation chain formation and chain dynamics that make variation in viscoelastic properties of magnetorheological (MR) fluids. The formation and deformation of chain like structures in MR fluids at room temperature has been studied under the application of shearing force and externally applied magnetic field. The morphological investigation of MR fluid particles has been studied using SEM. A rheomicroscopy set-up was used to record the in-situ videos under magnetic field’s influence and a sequence of images were taken whose analysis has been performed using ImageJ. The plot of chain length versus shear rate at constant magnetic fields reveals the competitive nature of dipole–dipole interactions and shear forces acting simultaneously.

In this review article, the potentials of the nanoarchitectonic approach are demonstrated from the viewpoint of the high capability of structure formation from simple fullerene units. The formation of materials with huge morphological variety from simple unit components, fullerenes (C60 and C70), only through conventional procedures is exemplified. Although fullerenes are zero-dimensional units made only from a single element component, carbon, nanoarchitectonic processes from fullerene molecules provide one-dimensional, two-dimensional and three-dimensional motifs, and a further extension to complicated morphologies and hierarchical structures. The novel applications of nanoarchitected fullerene materials are also described by showing their usages in micro-scale material recognition and fate regulation of living cells. It is said that true innovation relies on the idea to create one from zero. This review article demonstrates this true innovation capability of nanoarchitectonics in material advances.

The increasing urbanization of urban areas poses the challenge of the development of materials capable of self-cleaning from organic pollutants formed. Previous papers substantiated the possibility of the coating of titanium oxide as the main agent of the photocatalytic method of cleaning structural materials on silica raw materials in order to increase the degree of its distribution in the volume of cement matrix and, as a result, increase its efficiency.It is obvious that a silica substrate will affect the processes of structure formation during hardening of a cement matrix. During the research, the processes of phase transformations of cement stone modified with silica raw materials of natural and technogenic origin were studied. As a result, the influence of siliceous modifiers on the strength characteristics of the cement stone was determined, which allowed ranking them according to the degree of decrease in efficiency as follows: technogenic raw materials; natural raw materials of silicate composition; natural raw materials of aluminosilicate composition. Quantitative assessments of the degree of efficiency showed the irrationality of using aluminosilicate composition as a silica modifier of natural raw materials, which is explained by its low pozzolanic activity.

The formation of subsurface particulate films when certain inorganic materials are vacuum deposited on softened polymer substrates is known for long. The subsurface structure formation is dependent on thermodynamic as well as deposition conditions. The subsurface particulate structure is similar to the discontinuous films under the polymer cover. The discontinuous films do exhibit certain interesting properties and the exploitation of these properties is constrained by the instabilities in their properties in vacuum as well as the degradation in atmosphere. The subsurface particulate structures are believed to be a solution against the instabilities of discontinuous films. Further, the morphology of the subsurface particulate structures is strongly dependent on the nature of the polymer and the polymer metal interaction. While interacting polymers like poly(2-vinylpyridine) (P2VP) and poly(4-vinylpyridine) (P4VP) suffer from the hygroscopic nature, inert polymers like polystyrene (PS) do not facilitate organised structure with small particles and small separations. The modifications of an inert polymer like PS by blending with an interacting polymer like P4VP, by electron beam irradiation to create free radicals, by doping with surfactants like 3-mercaptopropyltrimethoxysilane (MPTMS), by creating pre-nucleation centres with selenium have been carried out. The silver particulate films on such modified softened polystyrene substrates show interesting optical, structural and electrical properties. Some of these results are discussed in the article.

Composites MoSi2–ZrB2–SiC and MoSi2–HfB2–SiC were investigated in this study as the prospective materials for high-temperature industrial heaters. The composites with relative density 97–98% were produced by combustion synthesis followed by hot pressing. The macrokinetic features of combustion, as well as phase and structure formation mechanisms in the combustion waves, were analyzed and their influence on the structure, mechanical properties, and performance of heaters were ascertained. The mechanical and electrical properties of the heating elements produced in this work are considerably higher as compared to conventional MoSi2 counterparts. Among the investigated compositions, the MoSi2–HfB2–SiC demonstrated the highest resistance to high-temperature oxidation. Both compositions featured the formation of a stable continuous oxide layer consisting of crystalline α-quartz (high-temperature modification of SiO2) reinforced by ZrO2, ZrSiO4, HfO2, and HfSiO4 precipitates.

The course of the grafted polymerization of 2-hydroxyethylmethacrylate on polyvinylpyrrolidone with the formation of a reticulated copolymer with simultaneously chemical reduction of nickel ions is confirmed. The influence of the reduction process on the structural parameters of the polymeric matrix – the grafting efficiency and the content of polyvinylpyrrolidone in the copolymer, the molecular weight between crosslinks is established. The influence of the presence of polymer-monomer composition components on the particles formation of nickel filler is investigated. It has been found that the nickel ions reduction during the polymerization process promotes a uniform distribution of the formed metal particles in the polymer matrix volume.

The processes of structure formation in arc-PVD Ti–Cr–N coatings are studied by computer simulation methods. A new approach to defining the geometric space for determining the positions of atoms relative to the formed dimers and crystallites is proposed. The structure parameters are calculated, and the processes of structure formation in coatings at a potential of 120 V are studied.

Magnetic fields are a dynamically important agent for regulating structure formation in the interstellar medium. The study of the relative orientation between the local magnetic field and gas (column-) density gradient has become a powerful tool to analyse the magnetic field's impact on the dense gas formation in the Galaxy. In this study, we perform numerical simulations of a non-gravitating, isothermal gas, where the turbulence is driven either solenoidally or compressively. We find that only simulations with an initially strong magnetic field (plasma-$��, accepted for publication by MNRAS

Recently, the exploration of a new strategy to create pores on carbon frameworks has received great interest. Herein, the selectively tailoring of the covalent bonding method has been shown to be one of the effective methods to generate pores based on graphitic hollow carbon frameworks (HGC). The mechanism of porous structure formation is due to directional clipping of sp2 C–C- and C O covalent bonds into C–O bonds. Due to the effectively ability for selective tailoring of covalent bonds, the resulting porous HGC has dielectric transition behavior from conductive loss to dipole polarization dependent type, which is greatly beneficial to electromagnetic absorption. The results show that the porous HGC developed by this method has exceptionally EM absorption capacity, and the maximum qualified absorption bandwidth (fE) is 7.7 GHz at the thickness of 2.2 mm. Therefore, this work opens up a potential method for the design and synthesis of high-performance EM absorbers.

The research is devoted to the determination of the properties of the components of the developed milk-containing thermostable fillings and the establishment of the dependence of the effective viscosity on the temperature of the model system. In the work, studies are carried out for a model system containing xanthan gum; a model system containing tara gum; model system containing gelatin; a model system containing xanthan gum and tara gum; a model system containing xanthan gum, tara gum and gelatin; a model system containing xanthan gum, tara gum and sugar; model system containing xanthan gum, tara gum, skimmed milk powder; a model system containing xanthan gum, tara gum and maltodextrin. In this work, the dependence of the effective viscosity on the temperature of the model system is established. To achieve the aim, the following objectives are set: - determination of the dependence of the effective viscosity on the temperature of model systems with xanthan gum, tara gum, gelatin, sugar, skimmed milk powder and maltodextrin with different concentrations of these components; - establishment of the temperature range in which a sharp increase in the effective viscosity of the investigated model systems begins. An increase in the temperature of the system prevents gelation due to an increase in the intensity of Brownian motion and a decrease through it in the duration of the existence of bonds that arise between macromolecules. At the same time, a decrease in temperature promotes gelation, since this increases the number of contacts between macromolecules, which contributes to an increase in the strength of the so-called spatial network. In the article, the dependences of the effective viscosity on the temperature of model systems with xanthan gum, tara gum, gelatin, sugar, skimmed milk powder and maltodextrin with different concentrations of these components are obtained. Based on the obtained dependences, the established temperature ranges in which a sharp increase in the effective viscosity of the studied model systems begins

To effectively exploit large-scale structure surveys, we depend on accurate and reliable predictions of non-linear cosmological structure formation. Tools for efficient and comprehensive computational modelling are therefore essential to perform cosmological parameter inference analyses. We present the public software package ReACT, demonstrating its capability for the fast and accurate calculation of non-linear power spectra from non-standard physics. We showcase ReACT through a series of analyses on the DGP and $f(R)$ gravity models, adopting LSST-like cosmic shear power spectra. Accurate non-linear modelling with ReACT has the potential to more than double LSST's constraining power on the $f(R)$ parameter, in contrast to an analysis that is limited to the quasi-linear regime. We find that ReACT is sufficiently robust for the inference of consistent constraints on theories beyond $\Lambda$CDM for current and ongoing surveys. With further improvement, particularly in terms of the accuracy of the non-linear $\Lambda$CDM power spectrum, ReACT can, in principle, meet the accuracy requirements for future surveys such as Euclid and LSST., Comment: 14 pages, 5 figures, MNRAS accepted version. ReACT code available here: https://github.com/nebblu/ReACT

Epoxy-based porous monoliths are prepared by chemically induced phase separation. The roles played by N,N-dimethylformamide (DMF) in both curing and phase separation kinetics are studied in detail. It is found that the addition of DMF not only changes the speed of phase separation, but the way. Meanwhile, the occurrence of secondary phase separation is partly inhibited, which is in favor of the formation of skeletal network structure. In addition, the schematic pseudo phase diagrams were deduced, which are of great significance to understand the roles played by DMF for the targeted control of materials structure. The results show that by the addition of DMF, the phase diagram moves to the lower right, which means more porogen is needed to obtain skeletal network structure. The spinodal line moves toward the binodal line and the internal space of spinodal line is enlarged. Therefore, it becomes more available to obtain skeletal network structure.

Crystal structure and supramolecular organization of new segmented thermoplastic polyurethane ureas and their nanocomposites with ultra-small additives (less than 0.1 wt.%) of single-walled carbon nanotubes (SWCNTs) have been been investigated using DSC and X-ray diffraction analysis. Taking into account the Avrami model, effects of physical aging and thermal history of the samples on the crystallization rate was described. It was demonstrated that the introduction of ultra small amounts of SWCNTs does not decrease the crystallinity, but decreases the crystallization rate.

The paper describes the methodology of processing of the experimental data from the study of the hardening process of the binder paste, which allows to reveale information hidden in the results and objectively divide the period of structure formation into steps that differ in mechanisms and conditions. The proposed method has a universal character, is designed to study compositions of a heterogeneous structure and is implemented using experimental data on the plastic strength of gypsum binder paste as a simplified model of such a composition. It consists of two stages - the transition to normalized values and coordinate transformation to adequately display the observed processes of structure formation. To determine the type of the corresponding coordinate transformation, Erofeev and Kolmogorov equations were considered, which describe, in particular, crystallization processes. Based on the proposed equations, a physically reasonable choice of coordinate transformations of the re-logarithmic type was carried out. Processing the data on the plastic strength of the hardening gypsum binder paste as a model of the composition of an inhomogeneous structure allows us to identify the main stages of structure formation characterized by linear dependencies and transition stages in which qualitative transformations of the regime of change in plastic strength during hardening are observed. The separation of the total time of structure formation at the step is fixed on the graphs of changes in the corresponding properties, and the transition stages correspond to the points of change in the angular coefficients of the obtained dependencies. It is shown that the stationary step of structure formation corresponding to the stable maintenance of supersaturation is reflected in the general linear section on the graphs. It is shown that the time of occurrence of transition stages recorded during the measurement of plastic strength approximately corresponds to the setting time obtained by regulatory methods. A geometric interpretation of the angular coefficients of the obtained dependences which allows one to determine the structure of growing nuclei of a new phase was considered. The proposed technique can be applied to control the processes of structure formation of heterogeneous composition compositions.

A magnetic disc wind is an important mechanism that may be responsible for driving accretion and structure formation in protoplanetary discs. Recent numerical simulations have shown that these winds can take either the traditional `hourglass' symmetry about the mid-plane, or a `slanted' symmetry dominated by a mid-plane toroidal field of a single sign. The formation of this slanted symmetry state has not previously been explained. We use radially local 1D vertical shearing box simulations to assess the importance of large-scale MRI channel modes in influencing the formation and morphologies of these wind solutions. We consider only Ohmic resistivity and explore the effect of different magnetisations, with the mid-plane $\beta$ parameter ranging from $10^5$ to $10^2$. We find that our magnetic winds go through three stages of development: cyclic, transitive and steady, with the steady wind taking a slanted symmetry profile similar to those observed in local and global simulations. We show that the cycles are driven by periodic excitation of the $n=2$ or $3$ MRI channel mode coupled with advective eviction, and that the transition to the steady wind is caused by a much more slowly growing $n=1$ mode altering the wind structure. Saturation is achieved through a combination of advective damping from the strong wind, and suppression of the instability due to a strong toroidal field. A higher disc magnetisation leads to a greater tendency towards, and more rapid settling into the slanted symmetry steady wind, which may have important implications for mass and flux transport processes in protoplanetary discs., Comment: MNRAS accepted. 25 pages

This work investigates the formation of an ordered Ti3Al phase (α2 phase) in Ti–Al alloys as a function of the time and aging temperature. High-temperature treatment performed in the single-phase α field and the subsequent aging at different temperatures have been shown to result in more intense precipitation and growth of disperse particles than that resulted from pretreatment in the β field. The formation of a martensite structure during quenching complicates the subsequent transformation by the homogeneous mechanism.

Mesoporous β-MnO2 nanoparticles were synthesized by a template-free low-temperature crystallization of Mn4+ precursors (low-crystallinity layer-type Mn4+ oxide, c-distorted H+-birnessite) produced ...

Cellulosic nanomaterials constitute a topic of growing commercial interest for numerous applications, many of which demand a working knowledge of the rheology of the materials. We demonstrate here that aqueous suspensions of micro/nanofibrillated cellulose (MNFC) exhibit complex shear behavior governed primarily by fibrillar floc dynamics. Regimes corresponding to structure formation, persistence, and breakdown are quantitatively differentiated. We assess the recovery of the network structure as a function of the applied breakdown conditions and identify critical conditions that characterize the floc dynamics as isotropic or anisotropic. A two-step yield behavior generates persistent anisotropic flocs that effectively prohibit recovery of the initial gel structure under certain conditions. Processing within this stress window entails a risk of generating heterogeneous, potentially irreproducible structures and properties. An in-depth understanding of the rheology of aqueous MNFC suspensions and their floc-dominated, rather than fibril-dominated, nature is critical to rationally tailoring properties through judicious selection of processing conditions.

We present $\texttt{MG-evolution}$, an $N$-body code simulating the cosmological structure formation for parametrised modifications of gravity. It is built from the combination of parametrised linear theory with a parametrisation of the deeply nonlinear cosmological regime extrapolated from modified spherical collapse computations that cover the range of known screening mechanisms. We test $\texttt {MG-evolution}$, which runs at the speed of conventional $\Lambda$CDM simulations, against a suit of existing exact model-specific codes, encompassing linearised and chameleon $f(R)$ gravity as well as the normal branch of the Dvali-Gabadadz-Porrati braneworld model, hence covering both large-field value and large-derivative screening effects. We compare the nonlinear power spectra produced by the parametrised and model-specific approaches over the full range of scales set by the box size and resolution of our simulations, $k=(0.05-2.5)$~h/Mpc, and for two redshift slices, $z=0$ and $z=1$. We find sub-percent to one-percent level recovery of all the power spectra generated with the model-specific codes for the full range of scales. $\texttt {MG-evolution}$ can be used for generalised and accurate tests of gravity and dark energy with the increasing wealth of high-precision cosmological survey data becoming available over the next decade., Comment: 11 pages, 3 figures. Updated to match version published in Monthly Notices of the Royal Astronomical Society

Dark matter haloes play a fundamental role in cosmological structure formation. The most common approach to model their assembly mechanisms is through N-body simulations. In this work we present an innovative pathway to predict dark matter halo formation from the initial density field using a Deep Learning algorithm. We implement and train a Deep Convolutional Neural Network (DCNN) to solve the task of retrieving Lagrangian patches from which dark matter halos will condense. The volumetric multi-label classification task is turned into a regression problem by means of the euclidean distance transformation. The network is complemented by an adaptive version of the watershed algorithm to form the entire protohalo identification pipeline. We show that splitting the segmentation problem into two distinct sub-tasks allows for training smaller and faster networks, while the predictive power of the pipeline remains the same. The model is trained on synthetic data derived from a single full N-body simulation and achieves deviations of ~10% when reconstructing the dark matter halo mass function at z=0. This approach represents a promising framework for learning highly non-linear relations in the primordial density field. As a practical application, our method can be used to produce mock dark matter halo catalogues directly from the initial conditions of N-body simulations., 10 pages, 8 figures, 1 table, submitted to MNRAS, comments welcome

Cosmological density perturbations governed by Newtonian and MONDian force laws scenarios for the period from matter domination to recombination have been investigated. Particularly, we find solutions for the density contrast equations obtained for both cases with respect to a homogeneous spatially flat Friedman-Lemaitre-Robertson-Walker (FLRW) background using the Lie symmetry approach. Numerical solutions of the density contrast equations for both cases also have been provided in order to study the evolution of the density contrast. For the Newtonian case we find a limiting mass that dictates whether the growth of the density contrast is possible or not. Interestingly, in the Newtonian case, physical growth of the density contrast is not possible since the horizon mass is smaller than the limiting mass. On the other hand, growth of the density contrast is possible depending on the initial condition and the fluctuation mass of the MOND-dominated region despite the radiation pressure that leads to future structure formation.

In this study, molecular dynamics simulations were performed to understand the defect structure development of polyacrylonitrile-single wall carbon nanotube (PAN-SWNT) nanocomposites. Three different models (control PAN, PAN-SWNT(5,5), and PAN-SWNT(10,10)) with a SWNT concentration of 5 wt% for the nanocomposites were tested to study under large extensional deformation to the strain of 100% to study the corresponding mechanical properties. Upon deformation, the higher stress was observed in both nanocomposite systems as compared to the control PAN, indicating effective reinforcement. The higher Young’s (4.76 ± 0.24 GPa) and bulk (4.19 ± 0.25 GPa) moduli were observed when the smaller-diameter SWNT(5,5) was used, suggesting that SWNT(5,5) resists stress better. The void structure formation was clearly observed in PAN-SWNT(10,10), while the nanocomposite with smaller diameter SWNT(5,5) did not show the development of such a defect structure. In addition, the voids at the end of SWNT(10,10) became larger in the drawing direction with increasing deformation.

Steady-state interaction between stationary grains mediated by plasmas at ultracold superfluid helium temperatures is investigated using particle-in-cell (PIC) simulations with Monte-Carlo collisions. A wide-ranging parametric exploration of interdependence of the physical parameters and its consequence on overall grain–plasma dynamics for cryogenic dusty plasmas is presented. Charging of the grains and the density of trapped ions exhibit a remarkable dependence on the particle shape. Grain charging shares a direct relation with ion flow strength as well and manifests contrasting trends at flow strength $M_{\text {th}}\leq 5$ and $M_{\text {th}}\geq 5$ . A comparison of an isolated grain electric field and potential with the two-grain–plasma system asserts that the field due to an isolated grain is precisely of the same order as the two grain field at subsonic flows. Binding-energy range is estimated to be 0.16–22 eV at $M_{\text {th}}$ = 0–15 and supports the possibility of molecule-like dust structure formation at ultracold temperatures.

The structure formation influence on various macroscopic properties of disperse systems is poorly investigated in respect to emulsion systems. The present work deals with the experimental and theoretical study of the heat transfer in emulsions whose dispersed phase droplets are arranged into chain-like structures under the action of external force field. The studied emulsions are of water-in-oil and oil-in-water types; they are based on ferrofluid and contain dispersed phase droplets in a size range of the order of several tens of micrometers. It is demonstrated that the emulsion thermal conductivity grows notably under the effect of external magnetic field parallel to the heat flux and provoking structure formation. It is revealed that the maximal response of thermal conductivity on the magnetic field action takes place at the dispersed phase volume fraction of about 20–30%. The structure formation in magnetic field has been simulated, and the magnetic interactions of emulsion droplets with each other and with the sample boundaries have been considered and discussed. The macroscopic thermal conductivity of structured emulsions has been numerically calculated and compared with experimental data. The obtained results may be of interest in the development of potential applications of controlling the properties of colloids by magnetic field.

A model of discontinuous precipitation of γ′ phase at grain boundaries (GBs) in polycrystalline Ni-based superalloys during continuous cooling from supersolvus temperature was developed. The model calculates the size and γ′ phase fraction in GB precipitates as a function of cooling rate and GB mobility. The model is based on the classical mechanism of diffusion-controlled precipitation. It considers fast diffusion of γ′-forming elements along the GB and the motion of the GBs under driving force induced by alloy decomposition. The model predicts either discrete GB gamma-prime particles and GB serration or the growth of fan-type structures depending on the cooling rate and GB mobility. We conclude from the model predictions that the GB mobility is the key factor controlling the type and morphology of GB precipitates. High GB mobility results in formation of fan-type structures, while the lower GB mobility leads to GB serration. The predicted dependence of the size of GB precipitates on the cooling rate is in good agreement with the experimental observations.

A Landau-de Gennes formulation coupled with a mass-transfer equation was used to track the evaporation front and the development of chiral microstructures during the casting of sulfuric acid-hydrolyzed cellulose nanocrystal (CNC) films. These simulations are compared to thin-film casting experiments that used analogous processing parameters and environments. The results show that the initial concentration, chiral strength, surface anchoring, speed of drying, and the influence of initial shear alignment all affect the uniformity of the microstructure and the orientation of the chiral director. In this report, we aim to show that under optimal casting conditions, the lateral size of planar microstructural domains that exhibit uniform selective reflection can be achieved on the order of millimeters.

When following the growth of structure in the Universe, we propose replacing merger trees with merger graphs, in which haloes can both merge and split into separate pieces. We show that this leads to smoother mass growth and eliminates catastrophic failures in which massive haloes have no progenitors or descendants. For those who prefer to stick with merger trees, we find that trees derived from our merger graphs have similar mass growth properties to previous methods, but again without catastrophic failures. For future galaxy formation modelling, two different density thresholds can be used to distinguish host haloes (extended galactic haloes, groups, and clusters) from higher density subhaloes: sites of galaxy formation.

Chemically active particles suspended in a liquid solution can achieve self-motility by locally changing the chemical composition of the solution via catalytic reactions at their surfaces. They operate intrinsically out of equilibrium, continuously extracting free energy from the environment to power the dissipative self-motility. The effective interactions involving active particles are, in general, nonreciprocal and anisotropic, even if the particles have simple shapes (e.g., Janus spheres). Accordingly, for chemically active particles a very rich behavior of collective motion and self-assembly may be expected to emerge, including phenomena such as microphase separation in the form of kinetically stable, finite-sized aggregates. Here, I succinctly review a number of recent experimental studies that demonstrate the self-assembly of structures, involving chemically active Janus particles, which exhibit various patterns of motion. These examples illustrate concepts such as “motors made out of motors” (as suggestively named by Fischer [Fischer, P. Nat. Phys. 2018, 14, 1072]). The dynamics of assembly and structure formation observed in these systems can provide benchmark, in-depth testing of the current understanding of motion and effective interactions produced by chemical activity. Finally, one notes that these significant achievements are likely just the beginning of the field. Recently reported particles endowed with time-dependent chemical activity or switchable reaction mechanisms open the way for exciting developments, such as periodic reshaping of self-assembled structures based on man-made internal clocks.

The interpretation of cosmological observations relies on a notion of an average Universe, which is usually considered as the homogeneous and isotropic Friedmann-Lema\^itre-Robertson-Walker (FLRW) model. However, inhomogeneities may statistically bias the observational averages with respect to FLRW, notably for distance measurements, due to a number of effects such as gravitational lensing and redshift perturbations. In this article, we review the main known theoretical results on average distance measures in cosmology, based on second-order perturbation theory, and we fill in some of their gaps. We then comprehensively test these theoretical predictions against ray tracing in a high-resolution dark-matter $N$-body simulation. This method allows us to describe the effect of small-scale inhomogeneities deep into the non-linear regime of structure formation on light propagation up to $z=10$. We find that numerical results are in remarkably good agreement with theoretical predictions in the limit of super-sample variance. No unexpectedly large bias originates from very small scales, whose effect is fully encoded in the non-linear power spectrum. Specifically, the directional average of the inverse amplification and the source-averaged amplification are compatible with unity; the change in area of surfaces of constant cosmic time is compatible with zero; the biases on other distance measures, which can reach slightly less than $1\%$ at high redshift, are well understood. As a side product, we also confront the predictions of the recent finite-beam formalism with numerical data and find excellent agreement., Comment: 21+8 pages, 23 figures. Accepted version

The reaction mechanism of the formation of hybrid oligomers based on complexes compounds of metal and oligophenylene is considered. The structure of compounds formed in such a reaction is determined. The effect of the addition of dimethyl sulfoxide on the increase in the yield of the main reaction product was found, and a mechanism of this effect was proposed, based on the change in the conformational features of oligophenylene in the synthesis process. The produced oligomers are promising as binders for composites of superhard materials.

New composite materials based on AlN–Y2O3–С have been created for use as absorbers of microwave radiation in vacuum electronics. X-ray diffraction and structural studies have shown that the major phases in the structure of the composites are AlN (hexagonal and cubic), Y3Al5O12, Al3O4, and С. An increase of time of component mixing and grinding influenced structure formation, promoted an increase in the content of the Al3O4 phase, and led to enhancement of microwave radiation attenuation by the composites (from 6.5 to 7.6 dB), this being indicative of an increase in the absorption capacity of the ceramics obtained.

The forming mechanism of anomalous eutectic structure (AES) in undercooled eutectic alloys has been a controversial issue. In this work, we conducted in situ observation of the AES forming process in an Ni-18.7 at.% Sn eutectic alloy using a high-temperature laser scanning confocal microscope. Our results provide an evidence of the AES formation induced by remelting of primary eutectic lamellae constituted by Ni3Sn and α-Ni lamellae. During recalescence, a pronounced remelting of the Ni3Sn phase into liquid occurs, while the α-Ni lamellae subject to a rapid morphological transition into granules. Eventually, the completion of solidification leads to the AES formation.

We studied the effect of the composition and dopants on the structure of a SiC–Al2O3 composite. The density, porosity, and morphological features of the structure were considered. The physicomechanical properties of the obtained samples, such as flexural strength and hardness, were explored. The optimal values of these characteristics are found relative to the compositions and technological modes of production.

To clarify the structure formation in pH-sensitive cellulose based micro porous membrane in non-solvent-induced phase separation process, first, a series of ethyl cellulose-graft-poly(2-(di...

Revealing the mechanisms of self-organized core-shell (C-S) structure in immiscible systems has drawn considerable attentions, however, the further and fundamental understanding from the point of view of phase-separated pattern remains extremely rare. In this work, by realizing two phase-separated patterns in transparent immiscible system, namely nucleation-growth and spinodal decomposition, their effects on radius of minority-phase droplet (MPD) were examined, and subsequently the effect on C-S structure was further determined. It was found that compared with MPDs produced via nucleation-growth, the MPDs via spinodal decomposition are much larger and easier to form a C-S structure. This is mainly because the larger MPDs can migrate faster and are earlier to reach the sample’s center. In addition, two pathways of core formation were observed during the formation of C-S structure: one evolves from a ring-like structure in the phase separation of spinodal decomposition; the other derives from the collision of numerous MPD at sample’s center. Such a difference is ascribed to the combination of different growth kinetics and the volume fractions of MPD. These findings might provide an in-depth insight into the C-S structure formation in immiscible systems.

Special structure formation and rational component modulation are common strategies to obtain superior catalytic properties for fuel cell applications. Here, we propose a facile method to synthesiz...

The confinement of colloidal particles at liquid interfaces offers many opportunities for materials design. Adsorption is driven by a reduction of the total free energy as the contact area between the two liquids is partially replaced by the particle. From an application point of view, particle-stabilized interfaces form emulsions and foams with superior stability. Liquid interfaces also effectively confine colloidal particles in two dimensions and therefore provide ideal model systems to fundamentally study particle interactions, dynamics, and self-assembly. With progress in the synthesis of nanomaterials, more and more complex and functional particles are available for such studies. In this Account, we focus on poly(N-isopropylacrylamide) nanogels and microgels. These are cross-linked polymeric particles that swell and soften by uptaking large amounts of water. The incorporated water can be partially expelled, causing a volume phase transition into a collapsed state when the temperature is increased above approximately 32 °C. Soft microgels adsorbed to liquid interfaces significantly deform under the influence of interfacial tension and assume cross sections exceeding their bulk dimensions. In particular, a pronounced corona forms around the microgel core, consisting of dangling chains at the microgel periphery. These polymer chains expand at the interface and strongly affect the interparticle interactions. The particle deformability therefore leads to a significantly more complex interfacial phase behavior that provides a rich playground to explore structure formation processes. We first discuss the characteristic "fried-egg" or core-corona morphology of individual microgels adsorbed to a liquid interface and comment on the dependence of this interfacial morphology on their physicochemical properties. We introduce different theoretical models to describe their interfacial morphology. In a second part, we introduce how ensembles of microgels interact and self-assemble at liquid interfaces. The core-corona morphology and the possibility to force these elements into overlap upon compression results in a complex phase behavior with a phase transition between microgels with extended and collapsed coronae. We discuss the influence of the internal particle architecture, also including core-shell microgels with rigid cores, on the phase behavior. Finally, we present new routes for the realization of more complex structures, resulting from multiple deposition protocols and from engineering the interaction potential of the individual particles.