bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulations of the Cabbeling Phenomenon in Surface Gravity Currents in Cold Fresh Water
Authors: George Alabodite Meipre , Kay Anthony 
Published: March 2022

The behaviour of warm water discharge at a temperature higher then Tm horizontally into a homogeneous body of cold fresh water at a temperature lower then Tm was investigated by means of a numerical model. Water density here was taken to be a quadratic function of temperature. Thus cabbeling process was inevitable as positively buoyant water form surface current while penetrating the ambient water. The current halted as mixture became dense and sink. These results are very similar to the experimental study of warm discharge into cold water by Marmoush et al. [14] and Bukreev [22]. The results showed an initially sinking water at the point where the two water bodies meets within the first few time interval. Development of Rayleigh-Taylor instabilities was observed at the lower part of the surface current as lighter fluid penetrate further. The frontal head was found to being replenished by a surface flow of warm unadulterated water, but after much entrainment of ambient fluid and cabbeling then, this head halted and sink. On the floor, denser fluid advance in the same direction as the original surface current, with some degree of Kelvin-Helmholtz instability as it penetrates further. Relations were also drawn that describes the speed, the spread length of both surface current were obtained.
Relation were also drawn that describes the final spread length of the surface current Lsm and the time taken to reach that final spread length Tsm as a function ϕin. This work as presented here is practical and relevant to many fields of study and also enhances policy making towards the protection of the aquatic ecosystems.
Genetic diversity and origin of a fish population recently colonizing a reservoir: The case ofBasilichthys microlepidotus, central Chile
Authors: Cortes‐Miranda Jorge , Véliz David , Flores‐Prado Luis , Sallaberry Michel , Vega‐Retter Caren 
Published: March 2022

AbstractFreshwater ecosystems are among those most affected by human activity. Constructing artificial reservoirs can change freshwater biodiversity, thereby impacting genetic diversity (GD), which is crucial to population‐level adaptation. The Maipo River basin, inhabited by the endemic silversideBasilichthys microlepidotus, is one of Chile's most impacted freshwater systems. In this basin, the species is divided into five populations. Recently, a new population was discovered in the reservoir Laguna Esmeralda (LE). We hypothesized that LE silversides possess less GD than other populations and originated from a single basin population. Our evidence shows that the LE is a genetically isolated population with evidence of low genetic variation, but not showing signals of bottleneck or significant reduction in GD. Results consistently identified two sites as unlikely to be the origin of the LE silverside population, suggesting that it was established by the immigration of many individuals from the other three populations.
Emerging Trends in Ring‐opening Metathesis Polymerization
Authors: Cao Edgar , Pichavant Loïc , Trinh Thi Kim Hoang , Chemtob Abraham , Quémener Damien , Pinaud Julien , Héroguez Valerie 
Published: March 2022

AbstractThis article presents the different techniques and strategies that have been explored over the last decade to overcome synthetic challenges and produce a wide range of new (nano)materials by ring‐opening metathesis polymerization (ROMP). In a first part, recent developments in photochemically activated ROMP are critically discussed. The second part is devoted to the synthesis of nanoparticles in dispersed media and by self‐assembly. The last two parts are dedicated to two interesting ROMP developments, the first in the medical field and the last part on different separation techniques.
Polymeric Dispersants
Authors: Pirrung Frank , Auschra Clemens 
Published: March 2022

Abstract
This article provides an overview on the numerous approaches that have been developed for several decades for a major class of coating and printing ink additives often referred to as polymeric pigment dispersants. The first part of this article will focus on the polymer architectures, the anchoring mechanisms, types of particle surfaces, the suitable anchoring groups, and explains how the different particle stabilization mechanisms have been realized in the design of the polymers. In the following chapters, the dispersants will be classified according to their main polymer chemistry, and details will be given on the building blocks and processes employed for industrial production for each class of pigment dispersants. It will be shown, how they can be adapted towards different end use applications ranging from solvent‐free, solvent‐based to aqueous systems. This article will address in detail the “classical” major dispersant classes of commercial importance in the coatings industry based on polyacrylates, polyesters, polyurethanes, and polyacids. In addition, we will especially review recent developments based on controlled polymerization techniques using GTP, ATRP, NMP, and RAFT, as such dispersants are gaining increasing importance for the most demanding applications like for nano‐sized pigments in applications such as inkjet or electronics.
Macromolecular Rheology
Authors: van Ruymbeke Evelyne , Vlassopoulos Dimitris 
Published: March 2022

AbstractOne of the most important features of polymeric systems is their response to weak external stimuli. Of utmost importance is their reaction to an imposed mechanical load, which reflects their viscoelasticity. The viscoelastic properties of polymers are central to their handling and are responsible for their wide‐ranging applications. In this article, we provide the basic elements of molecular rheology, the science of deformation and flow of matter, which is necessary for understanding polymer viscoelasticity and linking it to molecular characteristics of the studied macromolecules. The presentation is basic and does not require prior knowledge on the topic. It refers to amorphous flexible polymers with emphasis on melts. First, the fundamental aspects of rheological measurements are discussed, followed by a discussion on linear viscoelasticity. Then, the models for the linear viscoelastic response of both unentangled and entangled polymers are presented in detail for different architectures, linear, star, and well‐characterized branched polymers. Subsequently, we focus on the nonlinear viscoelastic regime with particular emphasis on the current state‐of‐the‐art and remaining challenges. Where appropriate, some applications of interest to the industrial practice are briefly discussed. Nonlinear phenomena such as flow instabilities, flow‐induced crystallization, and wall slip are not covered.
Additive Manufacturing of Polymers: 3D and 4D Printing, Methodologies, Type of Polymeric Materials, and Applications
Authors: González‐Henríquez Carmen M. , Sarabia‐Vallejos Mauricio A. , Sanz‐Horta Raul , Rodriguez‐Hernandez Juan 
Published: March 2022

AbstractThis article is devoted to the use of polymers in additive manufacturing (AM), also generally known as 3D printing or rapid prototyping. AM presents essential advantages in comparison to traditional fabrication methodologies since it allows the fabrication of wholly customized 3D parts and objects with astonishing levels of geometrical complexity. Moreover, AM entails a significant reduction in the fabrication time, and therefore, parts can be fabricated with a substantial cost reduction. While different materials can be employed for 3D printing, including metals and ceramics, polymers are without any doubt the most versatile, and their use is increasingly growing.In this article, we aim to provide a clear overview of the principles in which are based the different AM technologies that employ polymers for the fabrication of 3D objects. The particularities of each technology including advantages/disadvantages and type of polymers used will be presented. Consequently, an extensive overview of the applications of the 3D‐printed structures will be provided, covering different areas ranging from biomedical purposes to the fabrication of microfluidic devices. This article also introduces the concept of 4D printing and presents some of the current analysis of the environmental aspects associated with AM and the future of this technology.
Tough Hydrogels Based on Sacrificial Bond Principle
Authors: Cui Kunpeng , Gong Jian P. 
Published: March 2022

Abstract
Hydrogels are swollen polymer networks in water and are usually considered as a type of mechanically weak materials. In recent years, by using sacrificial bond principle, many strong and tough hydrogels were developed, widely extending their application to various fields. The sacrificial bonds break preferentially during deformation, dissipating a significant amount of energy and giving a high toughness of the hydrogels. Diverse sacrificial structures have been used to toughen hydrogels, with structure length ranging from nanometer scale to millimeter scale. Different sacrificial structures cause very different specific molecular mechanisms and properties of hydrogels. In this article, the molecular mechanisms of various tough hydrogels are summarized, and the synergistic effect by combining multiple energy dissipation mechanisms to achieve super‐tough hydrogels is highlighted.
Flow‐Induced Crystallization of Semicrystalline Polymer
Authors: Chen Wei , Sheng Junfang , Yu Wancheng , Li Liangbin 
Published: March 2022

AbstractThis article summarizes our recent efforts to understand the fundamental mechanism of flow‐induced crystallization of semicrystalline polymers in the melt state. Three general experimental phenomena for polymer crystallization underflow are presented first, which are related to crystal morphology, polymorphism, and crystallization kinetics. Then, theoretical efforts to clarify the above phenomena are briefly summarized. The validation of coil‐stretch transition proposed by de Gennes and the stretched network model in flow‐induced crystallization of polymers is discussed. We proposed a new thermodynamics scenario to quantify the nucleation barrier through decoupling the contribution of conformational entropy and segmental orientation order of initial deformed melt. We also incorporated the crystal morphology and polymorphism into calculating the free energy of nuclei. The proposed model can well agree with the experimental observations. Finally, we present some recent synchrotron radiation X‐ray scattering and molecular dynamics simulation results, which challenge the classical one‐step nucleation model. These results suggest a multistep ordering of flow‐induced nucleation, which is discussed in detail.
Polymeric Membranes
Authors: Nunes Suzana P. 
Published: March 2022

Abstract
Polymeric membranes are constantly expanding their applications in separations going from desalination to hydrocarbon recovery and fractionation in the petrochemical industry. They are superior in terms of processability and scalability when compared to inorganic analogues. The diversity of chemistry allows to design membranes with tune porosity and functionality optimized for different applications. This article gives an overview of the main methods of membrane preparation and discusses the field challenges and opportunities. It considers how substituting the classical materials by more stable ones can open the door for applications in the chemical industry, how building blocks with preformed cavities can increase selectivity to level not demonstrated before, and how the criterion of sustainability is changing the strategies, materials, and solvents in the membrane fabrication.
Macromolecular Engineering by Photochemical Routes
Authors: Yılmaz Gorkem , Yagci Yusuf 
Published: March 2022

Abstract
Applications of photochemical processes have been revitalized and rapidly expanding, especially after its indisputable advantages in comparison to conventional methods have been realized. These advantages include low energy requirements, environmentally friendly processing, mildness, and modularity. As such, photochemical strategies meet the requirements of green chemistry, which is perhaps the most important demand as we move to a more sustainable world. The most important application of photochemistry to polymer synthesis is definitely photopolymerization, which is the typical process that transforms monomers into polymers through photon energy. The use of photoinitiators in such systems is of high priority as they lead to the generation of the reactive species responsible for initiation. Photopolymerization can be applied to both chain and step‐growth polymerizations, though the former is in more advanced state. For chain polymerizations, free radical and cationic photoinitiators can be employed.
Polymeric Materials for Additive Manufacturing
Authors: Weyhrich Cody W. , Scott Philip J. , Williams Christopher B. , Long Timothy E. , Hmeidat Nadim S. , Wimmer Madeline , Romberg Stian K. , Compton Brett G. , Levenhagen Neiko , Dadmun Mark 
Published: March 2022

AbstractAdditive manufacturing (AM), also known as 3D printing, is a promising technology to produce complex shapes with little waste material in a distributed fashion. AM can be implemented with various materials, but metal and polymer are dominant feedstocks. During the deposition process for polymeric AM, the polymer may encounter repetitive softening or melting, applied shear flow including multiple constrictions, cooling and solidification, solvent evaporation, polymerization and crosslinking, or coalescence across interfaces. This leads to the need to invoke polymer science principles to rationally predict the response of the polymeric feedstock to the shear fields, thermal gradients, and reaction fronts that they will encounter in the complex 3D printing process. Elucidating the fate of the macromolecules as they experience the 3D printing process provides a foundation to design new materials that are formulated to bias the formation of robust structures and interfaces. As such, polymers in AM offer a unique opportunity to apply polymer science principles to address shortcomings, offer potential solutions, and advance the technology. This article provides a focused discussion of how polymer science principles drive the growth of three common polymeric AM techniques, fused filament fabrication, direct‐ink write, and vat polymerization.
Polymer Nanocomposites
Authors: Alkhodairi Husam , Bilchak Connor , Chan Sophia Y. , Jhalaria Mayank , Kumar Sanat K. , Tannenbaum Robert J. 
Published: March 2022

AbstractThere has been significant interest in polymer nanocomposites (PNCs) because of their promising property enhancements – however, achieving these improvements are contingent on controlling the nanoparticle (NP) dispersion state in the polymer matrix. The inherent incompatibility between a hydrophilic filler and a hydrophobic polymer is the ultimate barrier for obtaining controlled NP spatial dispersion. We can mediate this unfavorable interaction by incorporating moieties on the chains that interact favorably with the NP surface, but preparation strategies typically used to prepare nanocomposites, e.g., casting from a common solvent or melt blending, frequently result in (far) out‐of‐equilibrium NP dispersion states with the degree of non‐equilibrium character sensitively dependent on the particular preparation technique employed. This is due to the energy landscape of even a simple PNC material being very highly complex with many local equilibria and large barriers. Most theoretical studies and our current understanding are based on the assumption that an equilibrium description of the nanocomposite applies, i.e., the system attains its global minimum state. However, different preparation conditions can place the system in different local basinsandthe extremely slow relaxation times of these systems to go from the “as cast” state to the equilibrium state imply that nanocomposites can end up in out‐of‐equilibrium conditions,including stateswhere properties might be favorable. These points, which are elaborated in this review, speak to the importance of preparation and annealing conditions in the NP dispersion state and hence the properties of this novel class of materials. This topic is the focus of this chapter.
Anionic Polymerization of Vinyl and Related Monomers
Authors: Fontanille Michel , Gnanou Yves 
Published: March 2022

AbstractVinyl, vinylidene, (meth)acrylic monomers, conjugated dienes can undergo polymerization upon repeated nucleophilic attacks and additions on to their carbon‐carbon double bonds, generating carbanionic growing species. In absence of protic impurities or molecular groups that can react with these propagating carbanionic centers, the latter can be preserved indefinitely. Besides describing the essential features of anionic polymerization, of its initiation and propagation steps, this review also focuses on the opportunities unleashed in macromolecular engineering by the “living” nature of anionic polymerization. Examples of well‐defined macromolecular architectures obtained by anionic polymerization are reported.
Epilogue: Sorting, Depolymerizing, and Recycling Polymers: The Long Road to a Circular Plastics Economy
Authors: Gnanou Yves 
Published: March 2022

AbstractAfter Hermann Staudinger laid the foundations of polymer science 100 years ago, an extraordinary scientific, technological, and industrial saga has been written by a long list of academic and industrial scientists. As a result, polymers are present in practically all sectors of human activity, transforming human societies in terms of quality of life, safety, hygiene, etc. Yet the expansion in the production and use of polymeric materials comes at a price for the environment because the polymer economy has been organized since its inception under the “take, make, dispose” pattern. Such a linear organization of the polymer economy causes considerable damages to the environment, wastes resources, and harms wildlife. This article discusses the steps that need to be taken worldwide to turn a still linear polymer economy into a circular one. Questions such as the sorting of polymer waste, their mechanical recycling, their recycling through nonchemical processes, the depolymerization of some polymers into monomers, the pyrolysis of nondegradable polymers, the potential of biodegradation processes are critically reviewed. Recommendations are made in this article to dramatically reduce the carbon footprint of the whole production chain from monomer synthesis to the manufacture of polymers and build a truly circular polymer economy withreuse, repair, and recycleas its foundations.
Cardiac metabolic changes on 18F‐positron emission tomography after thoracic radiotherapy predict for overall survival in esophageal cancer patients
Authors: Zakem Sara J , Jones Bernard , Castillo Richard , Castillo Edward , Miften Moyed , Goodman Karyn A , Schefter Tracey , Olsen Jeffrey , Vinogradskiy Yevgeniy 
Published: March 2022

AbstractPurposeHeart doses have been shown to be predictive of cardiac toxicity and overall survival (OS) for esophageal cancer patients. There is potential for functional imaging to provide valuable cardiac information. The purpose of this study was to evaluate the cardiac metabolic dose–response using 18F‐deoxyglucose (FDG)–PET and to assess whether standard uptake value (SUV) changes in the heart were predictive of OS.MethodsFifty‐one patients with esophageal cancer treated with radiation who underwent pre‐ and post‐treatment FDG–PET scans were retrospectively evaluated. Pre‐ and post‐treatment PET‐scans were rigidly registered to the planning CT for each patient. Pre‐treatment to post‐treatment absolute mean SUV (SUVmean) changes in the heart were calculated to assess dose–response. A dose–response curve was generated by binning each voxel in the heart into 10 Gy dose‐bins and analyzing the SUVmean changes in each dose‐bin. Multivariate cox proportional hazard models were used to assess whether pre‐to‐post treatment cardiac SUVmean changes predicted for OS.ResultsThe cardiac dose–response curve demonstrated a trend of increasing cardiac SUV changes as a function of dose with an average increase of 0.044 SUV for every 10 Gy dose bin. In multivariate analysis, disease stage and SUVmean change in the heart were predictive (p < 0.05) for OS.ConclusionsChanges in pre‐ to post‐treatment cardiac SUV were predictive of OS with patients having a higher pre‐ to post‐treatment cardiac SUV change surviving longer.
Latent Mechanisms of Polarization Switching from In Situ Electron Microscopy Observations
Authors: Ignatans Reinis , Ziatdinov Maxim , Vasudevan Rama , Valleti Mani , Tileli Vasiliki , Kalinin Sergei V. 
Published: March 2022

AbstractIn situ scanning transmission electron microscopy enables observation of the domain dynamics in ferroelectric materials as a function of externally applied bias and temperature. The resultant data sets contain a wealth of information on polarization switching and phase transition mechanisms. However, identification of these mechanisms from observational data sets has remained a problem due to a large variety of possible configurations, many of which are degenerate. Here, an approach based on a combination of deep learning‐based semantic segmentation, rotationally invariant variational autoencoder (VAE), and non‐negative matrix factorization to enable learning of a latent space representation of the data with multiple real‐space rotationally equivalent variants mapped to the same latent space descriptors is introduced. By varying the size of training sub‐images in the VAE, the degree of complexity in the structural descriptors is tuned from simple domain wall detection to the identification of switching pathways. This yields a powerful tool for the exploration of the dynamic data in mesoscopic electron, scanning probe, optical, and chemical imaging. Moreover, this work adds to the growing body of knowledge of incorporating physical constraints into the machine and deep‐learning methods to improve learned descriptors of physical phenomena.
Mechanical Resilience of Biofilms toward Environmental Perturbations Mediated by Extracellular Matrix
Authors: Zhang Qiuting , Nguyen Danh , Tai Jung‐Shen B. , Xu XJ , Nijjer Japinder , Huang Xin , Li Ying , Yan Jing 
Published: March 2022

AbstractBiofilms are surface‐associated communities of bacterial cells embedded in an extracellular matrix (ECM). Biofilm cells can survive and thrive in various dynamic environments causing tenacious problems in healthcare and industry. From a materials science point of view, biofilms can be considered as soft, viscoelastic materials, and exhibit remarkable mechanical resilience. How biofilms achieve such resilience toward various environmental perturbations remain unclear, although ECM has been generally considered to play a key role. Here,Vibrio cholerae(Vc) is used as a model organism to investigate biofilm mechanics in the nonlinear rheological regime by systematically examining the role of each constituent matrix component. Combining mutagenesis, rheological measurements, and molecular dynamics simulations, the mechanical behaviors of various mutant biofilms and their distinct mechanical phenotypes including mechanics‐guided morphologies, nonlinear viscoelastic behavior, and recovery from large shear forces and heating are investigated. The results show that the ECM polymeric network protects the embedded cells from environmental challenges by providing mechanical resilience in response to large mechanical perturbation. The findings provide physical insights into the structure–property relationship of biofilms, which can be potentially employed to design biofilm removal strategies or, more forward‐looking, engineer biofilms as beneficial, functional soft materials in dynamic environments.