**Contents**


**Yago Chamoun F. Soares, Elyff Cargnin, Monica ˆ Feijo´ Naccache and Ricardo Jorge E. Andrade** Influence of Oxidation Degree of Graphene Oxide on the Shear Rheology of Poly(ethylene glycol) Suspensions Reprintedfrom:*Fluids***2020**,*5*,41,doi:10.3390/fluids5020041**163**

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## **About the Editors**

**Maria Teresa Cidade** is a member of the Polymeric and Mesomorphic Materials Group of the Faculty of Sciences and Technology of the New University of Lisbon (FCT NOVA), Portugal. She graduated in Chemical Engineering (IST/Technical University of Lisbon, 1983) and obtained a Ph.D. degree from FCT NOVA (1994). In 2006, she was appointed with the Habilitation in Polymer Engineering. Currently, she is an Assistant Professor with Habilitation at the Materials Science Department (DCM) of FCT NOVA. She is the Coordinator of the Polymeric and Mesomorphic Materials Group of DCM, Coordinator of the Rheology Sub-Group of the Soft and Bifunctional Materials Group of the Materials Research Centre (Cenimat) of DCM, Coordinator of the Doctoral Program in Materials Science and Engineering, and Coordinator of FCT NOVA in the Doctoral Program in Advanced Materials and Processing (a Doctoral Program in Association with six other Portuguese Universities: Lisbon, Coimbra, Beira Interior, Aveiro, Porto, and Minho, supported by the Portuguese Foundation for Science and Technology). She is the President of the Portuguese Society of Rheology, Associate Editor of *Physica Scripta* (IOP), and a member of the Editorial Board of *Fluids* (MDPI). Her main scientific interests include the rheology (including electrorheology and rheooptics) of complex systems (polymers and polymeric base systems, liquid crystals, nanocomposites, biomaterials, building materials, etc.), the mechanical characterization of polymers and polymer composites, and polymer processing. During her career, she has supervised more than 30 researchers, coauthored four book chapters and 79 papers in international refereed journals, lodged 1 patent, and presented more than 100 communications in conferences.

**Jo˜ao Miguel N´obrega** (Associate Professor) works at the Polymer Engineering Department of the University of Minho and is a member of the Institute for Polymers and Composites. In 2004, he received his Ph.D. degree from the University of Minho in Polymer Science and Engineering. He is the Editor of the OpenFOAM-R Journal and OpenFOAM-R Wiki, a founder member of the Iberian OpenFOAM-R Technology Users, and the lead faculty of the Digital Transformation in Manufacturing area from the MIT Portugal Program. His research activities encompass three overlapping areas: product development, polymer processing, and material rheology. For this purpose, he has been developing computational rheology tools to model the flow of complex fluids in various polymer processing techniques. Regarding the product development area, he has been involved in the design and manufacture of polymeric products across several fields, comprising applications for health, textiles, sensoring/monitoring, construction, and mobility. In 2014, he joined the OpenFOAM-R Extend community, and has focused, since then, on the main numerical developments in this open-source computational library. In 2016, he was the chair of the 11th Workshop OpenFOAM, which took place in Guimaraes, Portugal. During his career, he was involved in the supervision of ˜ more than 50 researchers, working both in fundamental and applied research projects; he has coedited 4 books, and published more than 80 papers in international refereed journals and 22 book chapters, lodged 9 patents (3 international), and presented approximately 200 communications in conferences.

*Editorial*

#### **Editorial for Special Issue "Advances in Experimental and Computational Rheology, Volume II"**

**Maria Teresa Cidade 1,\* and João Miguel Nóbrega 2,\***


Received: 21 September 2020; Accepted: 24 September 2020; Published: 25 September 2020

Rheology, defined as the science of the deformation and flow of matter, is a multidisciplinary scientific field, covering both fundamental and applied approaches. The study of rheology includes both experimental and computational methods, which are not mutually exclusive. Its practical relevance embraces many daily life processes, like preparing mayonnaise, spreading an ointment, or shampooing, and industrial processes, like polymer processing and oil extraction, among several others. Practical applications also include formulation and product development.

Following a successful first volume, the Special Issue entitled "Advances in Experimental and Computational Rheology", the editorial team decided to launch a second volume.

The Special Issue "Advances in Experimental and Computational Rheology, Volume II" comprises 10 papers covering some of the latest advances in the fields of experimental and computational rheology, applied to a diverse class of materials and processes, which can be grouped into three main topics: rheology [1–5], rheometry and processing [6,7], and theoretical modeling [8–10].

The characterization of rheological behavior is the main topic of five contributions, covering the following materials/systems: S-aureus cultures (Portela et al. [1]), in which antibiotic activity was screened by rheometry; natural hydraulic lime grouts filled with polypropylene fibers (Baltazar et al. [2]), with a particular focus on the effect of the measurement methods on the obtained yield stress; wheat flour dough (Macedo et al. [3]), where rheology was used as a tool to study the impact of whey powder addition on the dough and breadmaking performance; human milk (Alatalo et al. [4]), covering the influence of external factors on its characteristics; and graphene oxide/poly(ethylene glycol) suspensions (Soares et al. [5]), where the authors studied the influence of the oxidation degree of graphene oxide on the suspensions' shear rheology.

Two of the Special Issue papers are dedicated to rheometry and processing. Ibañez et al. [6] analyzed the ability of different machine learning techniques, able to operate under a low data limit, to create a model linking material and process parameters with the properties and performances of parts obtained by reactive polymer extrusion. Parlato et al. [7] applied the so-called Couette analogy concept, in order to achieve a reduction in the complex, non-viscometric rotational geometry to a virtual concentric cylinder analogue, allowing for the determination of the flow curve of non-Newtonian fluids in complex geometries.

Theoretical modeling is the main topic of the remaining three works. The work of Lopéz Aguilar et al. [8] put forward a modeling framework that was experimentally validated, with a focus on the circular abrupt contraction flow of two highly elastic constant shear viscosity Boger fluids, with various contraction ratio geometries. Pedro et al. [9] numerically studied the filling stage of thermoplastic injection molding with a solver implemented in the open-source computational library OpenFOAM® and compared the new solver performance and accuracy with a proprietary code. In the

work of OIshi et al. [10], the authors studied the gravitational e ffects of elasto-viscoplastic drops colliding on vertical planes and proposed a classification for the observed behaviors.

Finally, it is very important to recognize and acknowledge the e ffort put forth by the large number of anonymous reviewers, which was essential to assuring the high quality of all the contributions of this Special Issue.

**Conflicts of Interest:** The authors declare no conflict of interest.
