bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ideologemas del español en la primera mitad del siglo XX en Colombia
Authors: Molina Ríos Juliana Angélica 
Published: June 2019

El propósito del presente artículo es dar cuenta de algunos avances de orden teórico-interpretativo de la relación que existe entre las estructuras de poder que se configuran y se reproducen en la enseñanza del español y la vida política de Colombia. Así, la categorización que estructura los avances está directamente relacionada con la noción de ideologemas propuesta desde la perspectiva glotopolítica, por medio de la cual se establece la mirada hacia la legislación y los libros de texto del español. Se presenta la revisión de la legislación sobre la enseñanza del español que se produjo en Colombia durante el periodo de 1903-1949, desde el análisis de las ideologías lingüísticas, particularmente, los ideologemas. Desde esta perspectiva, se identificaron tres ideologemas centrales en dicha época: a) la lengua como dispositivo de blanqueamiento de la raza, b) la lengua como dispositivo de progreso y c) la lengua como elemento esencial en la consolidación de la nación. Derivado de este análisis, la reflexión final que surge está relacionada con cuáles ideologemas se mantienen o cambian en el periodo de 1980 y en el contexto actual de posconflicto en Colombia.
Ground States of a 𝐾-Component Critical System with Linear and Nonlinear Couplings: The Attractive Case
Authors: Wu Yuanze 
Published: June 2019

Abstract
Consider the system

{

-

Δ
⁢

u
i

+

μ
i

⁢

u
i

=

ν
i

⁢

u
i

2
*

-
1

+

β
⁢

∑

j
=
1

,

j
≠
i

k

u
j

2
*

2

⁢

u
i

2
*

2

-
1

+

λ
⁢

∑

j
=
1

,

j
≠
i

k

u
j

in

⁢
Ω

,

u
i

>
0

in

⁢
Ω

,

u
i

=
0

on

⁢

∂
⁡
Ω

,
i

=
1

,

2
,
…
,
k

,

\left\{\begin{aligned} \displaystyle-\Delta u_{i}+\mu_{i}u_{i}&\displaystyle=% \nu_{i}u_{i}^{2^{*}-1}+\beta\mathop{\sum_{j=1,j\neq i}^{k}}u_{j}^{\frac{2^{*}}% {2}}u_{i}^{\frac{2^{*}}{2}-1}+\lambda\mathop{\sum_{j=1,j\neq i}^{k}}u_{j}&&% \displaystyle\phantom{}\text{in}\ \Omega,\\ \displaystyle u_{i}&\displaystyle>0&&\displaystyle\phantom{}\text{in}\ \Omega,% \\ \displaystyle u_{i}&\displaystyle=0&&\displaystyle\phantom{}\text{on}\ % \partial\Omega,\quad i=1,2,\ldots,k,\end{aligned}\right.

where

k
≥
2

{k\geq 2}

,

Ω
⊂

ℝ
N

{\Omega\subset\mathbb{R}^{N}}

(

N
≥
3

{N\geq 3}

) is a bounded domain,

2
*

=

2
⁢
N

N
-
2

{2^{*}=\frac{2N}{N-2}}

,

μ
i

∈
ℝ

{\mu_{i}\in\mathbb{R}}

and

ν
i

>
0

{\nu_{i}>0}

are constants, and

β
,
λ

>
0

{\beta,\lambda>0}

are parameters. By showing a unique result of the limit system, we prove existence and nonexistence results of ground states to this system by variational methods, which generalize the results in [7, 18]. Concentration behaviors of ground states for

β
,
λ

{\beta,\lambda}

are also established.
Uncountably Many Solutions for Nonlinear Helmholtz and Curl-Curl Equations
Authors: Mandel Rainer 
Published: June 2019

Abstract
We obtain uncountably many solutions of nonlinear Helmholtz and curl-curl equations on the entire space using a fixed point approach. The constructed solutions are mildly localized as they lie in the essential spectrum of the corresponding linear operator. As a new auxiliary tool a limiting absorption principle for the curl-curl operator is proved.
Particle size and polymer formation dependence of nanostructure in antireflective surfaces by injection molding process
Authors: Kurihara Kazuma , Hokari Ryohei , Miyake Koji 
Published: June 2019

Abstract
The effects of nanomolding characteristics on an antireflective surface fabricated via injection molding were investigated. The optical property of a sub-wavelength structure (SWS) of our own making was also measured. The sizes of nanostructures fabricated on SWS molds were controlled by changing the average particle diameters used as mask and the time of reactive ion etching. The maximum filling ratio of the injected polymer was increased from 51.7% to 90.4% by changing the average particle diameters from 83.8 nm to 111.2 nm. In addition, the filled ratio of the injected polymer was increased from 51.7% to 73.7% under the same processing conditions. The results of the measurements of the optical property indicated that the reflectance of small-sized and large-sized SWSs fabricated with the same process condition was decreased at the wavelengths of 550 nm and 980 nm, respectively. The wavelength showed that the minimum reflectance was varied from the visible range to the near-infrared range by changing the size of the SWS under the same processing condition. This result led us to conclude that we can obtain antireflection surfaces for any wavelength by varying the size of the SWS under the same injection-molding condition.
Direct-write grayscale lithography
Authors: Grushina Anya 
Published: June 2019

Abstract
Grayscale lithography is used to produce three-dimensional (3D) structures on micro- and nanoscale. During the last decade, micro-optics and other applications were actively pushing the market demand for such structures. Direct-write systems that use lasers and heated scanning probes can be used for high-precision grayscale micro- and nanolithography. They provide solutions for the most demanding applications in research and industrial manufacturing. At both the micro- and nanoscale, though, some challenges remain, mainly related to throughput. Ongoing R&D efforts and emerging new applications drive several companies to join forces in order to meet the market demands for grayscale lithography of today and in the future.
A Rheological Fuzzy Model for Lime Plasticity and Mortar Consistency
Authors: Atzeni Cirillo , Sanna Ulrico , Spanu Nannina 
Published: June 2019

Abstract
This paper is concerned with a fuzzy model developed for describing the rheological properties of lime pastes and mortars. We have identified the physical parameters on which the flow properties of these materials depend, and whose complex interrelationships make it difficult to model the phenomena using a traditional approach. The basic notions of fuzzy modelling are described, a technique which enables different kinds of variables and other knowledge elements to be handled in a formal context that can be easily computerized. Applying the Fuzzy Approximation Theorem we can develop a model irrespective of whether the correlation functions are expressed in explicit analytical form or not. The definitions of the fuzzy sets for the different variables are provided which, together with IF/THEN rules comprise the knowledge base of the model. The model is then applied to determine the plasticity of lime pastes and consistency of lime-based mortars using ordinary fuzzy inference mechanisms.
Rheological Master Curves of Crystallizing Polymer Mixtures
Authors: Kapnistos M. , Vlassopoulos D. 
Published: June 2019

Abstract
We present a simple methodology for extending linear viscoelastic measurements of crystallizing polymers to the high-frequency regime, where usually crystallization kinetics represents an obstacle. The idea is to perform rapid quenches, below the melting temperature (which corresponds to the high-frequency region), account for the thermal equilibration and the very slow early stages of crystallization, and perform the measurements before really crystallization sets in, in the “quasi-equilibrium” state. Albeit tedious, when properly done, this method works remarkably well, as demonstrated for a particular polybutadiene mixture, and opens the route for obtaining rheological master curves in a wide variety of crystallizing polymers.
Morphology Development During Microconfined Flow of Viscous Emulsions
Authors: Vananroye Anja , Van Puyvelde Peter , Moldenaers Paula 
Published: June 2019

Abstract
In this contribution, a brief review is given of the dynamics of emulsions in microconfined shear flow. The interest in confined flow is triggered by the increasing importance of microfluidic applications in the processing industries. In a first part, some important aspects of confinement on single droplet dynamics are highlighted. The validity of the conclusions drawn from this part are subsequently applied to more concentrated systems. It is shown that microconfined emulsions can exhibit rich dynamics, and can display some peculiar morphologies.
Linear to Non-linear Rheology of Wheat Flour Dough
Authors: Ng Trevor S.K. , McKinley Gareth H. , Padmanabhan Mahesh 
Published: June 2019

Abstract
We provide an overview of transient extensional rheometry techniques for wheat flour doughs in which the deformation and material response is well defined. The behavior of a range of model doughs was explored with a Filament Stretching Extensional Rheometer (FISER). The measurements were also compared to data obtained with a new wind- up extensional rheometer; the SER universal testing platform. A simple empirical constitutive equation, which allows characterization of the experimental results with a small number of parameters, is presented to describe the resulting measurements. To characterize the relaxation modulus of the doughs, small amplitude shear tests were performed on samples that have been shear-mixed in a mixograph for varying lengths of time. The linear viscoelastic properties were found to exhibit a broad power-law dependence on the imposed oscillatory frequency that is very reminiscent of that exhibited by a critical gel. The critical gel model of Winter and Chambon [1, 2] was used as the basis for constructing a non-linear constitutive equation for the material stress by combining the relaxation modulus for the critical gel with a Lodge rubber-like liquid form for the kinematics. Transient uniaxial extensional data recorded from the FISER and SER instruments were then compared to the predictions of the constitutive equation. The model captures the initial power- law response and subsequent strain-hardening; however additional physics is required to describe the rheological phenomena at very large Hencky strains, including finite extensibility effects and filament rupture in extensional flows.
Rheological Behavior of Fugitive Organic Inks for Direct-Write Assembly
Authors: Therriault Daniel , White Scott R. , Lewis Jennifer A. 
Published: June 2019

AbstractThe rheological behavior of a fugitive organic ink tailored for direct-write assembly of 3D microfluidic devices is investigated. Rheological experiments are carried out to probe the shear storage and loss moduli as well as the complex viscosity as a function of varying temperature, frequency and stress amplitude. Master curves of these functions are assembled using time-temperature superposition. The fugitive ink, comprised of two organic phases, possesses an equilibrium shear elastic modulus nearly two orders of magnitude higher than that of a commercial reference ink at room temperature and a peak in the relaxation spectrum nearly six orders of magnitude longer in time scale. The self-supporting nature of extruded ink filaments is characterized by direct video imaging. Comparison of the experimentally observed behavior to numerical predictions based on Euler-Bernoulli viscoelastic beam analysis yield excellent agreement for slender filaments.
Mechanical and Structural Properties of Maltodextrin/Agarose Microgels Composites
Authors: Loret Chrystel , Frith William J. , Fryer Peter J. 
Published: June 2019

Abstract
We present results from a new approach to the study of multicomponent gels, which allows independent investigation of the effect of phase volume and droplet size of the dispersed phase on the mechanical properties of the mixed gel composites. The method involves preparation of agarose microgels with different sizes, which are then embedded in maltodextrin gel matrices with different gel strengths. The effects of both phase volume and droplet size on composite properties are dependent on the phase modulus ratio. The higher the phase modulus ratio, the larger is the reinforcement effect and the effect of droplet size on mechanical properties of the maltodextrin/agarose composites. The observed behaviour was compared with literature models for the behaviour of composite materials.
The ‘Yield Stress Myth?’ Paper – 21 Years On
Authors: Barnes Howard A. 
Published: June 2019

Abstract
Consideration is given to the reaction to Barnes and Walters’ 4-page ‘The yield stress myth?’ paper published 21 years ago. It has been cited approximately 180 times since then, as either a standard reference for ‘yield stress’ papers, or to disagree with its sentiment that yield stresses do not actually exist, but are a useful approximation. The references that cite the paper are categorized and commented on.
Influence of Molecular Weight of SAN on Rheological and Mechanical Properties of ABS-plastics
Authors: Dreval’ V.E. , Vasil’ev G.B. , Borisenkova E.K. , Semakov A.V. , Kulichikhin V.G. 
Published: June 2019

Abstract
Rheological and mechanical properties of acrylonitrile-butadiene-styrene polymers (ABS) prepared via bulk polymerization depending on the molecular weight (Mw) of styrene-acrylonitrile copolymer (SAN) have been investigated. The tendencies of attaining the yield stress at steady-state shear flow and approaching to the “plateau” region of storage modulus at low frequencies in oscillatory tests were observed. Both these phenomena are induced by formation of the structural skeleton consisting of polybutadiene (PB) particles arranged in the SAN-matrix. Growth of Mw of SAN leads both to increase of the “plateau” value of storage modulus at low frequencies and the yield stress. This fact can be explained by the influence of Mw of SAN chains grafted onto PB particles on structure formation in ABS melts because of a redistribution of the ratio particle-particle / particle-matrix interactions. The elongational viscosity of ABS melts is a power function of Mw of SAN matrix. The power index of this function increases with the polymer straining that reflects orientation of SAN chains with their length increase. The strain-hardening index of ABS melts increases considerably with increase of SAN matrix Mw. However, it does not depend on presence of PB particles in the material. It means that the value of this index is governed by orientation effect in the SAN matrix. The impact strength of the investigated ABS samples is interrelated with rheological characteristics of ABS melts as well as Mw of SAN. The dependence of impact strength on Mw can be explained by increasing role of orientation effects of SAN chains with Mw increase in the copolymer fibrils connecting the walls of crazes formed at impact action.
Evaluation of Time Independent Rheological Models Applicable to Fresh Self-Compacting Concrete
Authors: Feys Dimitri , Verhoeven Ronny , De Schutter Geert 
Published: June 2019

Abstract
Self-Compacting Concrete is a new type of concrete which is more liquid compared to traditional concrete and which does not need any form of external compaction. As a result this type of concrete is suitable for a new placing technique: pumping SCC from the bottom in the formwork and letting it rise in the formwork due to the applied pressure. In order to understand the phenomena occurring during pumping operations, the rheological properties of SCC must be investigated and controlled. Tests have been performed with two different rheometers, which are described in this paper. For the Tattersall Mk-II rheometer, a calibration procedure has been worked out to eliminate secondary flows in the rheometer. Test results indicate that SCC is a thixotropic liquid, having a yield stress, showing shear thickening and having varying properties in time due to the occurring chemical reactions. In this paper, the time dependent effects will not be described. When trying to apply a rheological model to the obtained results, only the modified Bingham model seems appropriate. Applying the Bingham model results in the generation of negative yield stresses while the Herschel-Bulkley model has a parameter with a variable dimension and has a major mathematical restriction. The rheological properties of fresh SCC can be described with the modified Bingham model. A suitable parameter to describe shear thickening is defined as the ratio of the second order term in the shear rate of the modified Bingham model to the linear term (= c/m).
The Nonlinear History of Fibre Flow Research. Part 2: Continuation, Reflections and Suggestions
Authors: Björkman Ulf 
Published: June 2019

Abstract
Technical fibre flows are normally flocky but have theoretically mainly been treated as individual fibre flows. The reason for this can only be understood through the subject’s historic development. In Part 1 of this investigation the origin of fibre flow research was traced to the beginning of the 19th century, and was followed through its formative years at the first half of the 20th century up to about WWII. This second and final part takes us up to about the 1960s when the present main theoretical research tradition had been firmly established. An example of an alternative approach is given. Finally, some suggestions for future work are advanced. In Appendix methods of characterising the inner geometry of technical fibre suspensions are discussed
Influence of Viscosity-Modifying Admixtures on the Thixotropic Behaviour of Cement Pastes
Authors: Bouras R. , Chaouche M. , Kaci S. 
Published: June 2019

Abstract
Water soluble polymers such as cellulosic or starch ethers are often included in the mix-design of Self Compacting Concretes (SCCs) in order to improve their stability and robustness. The stability, including resistance to liquid-solid separation and sedimentation, may be attributed to the increase of the viscosity of the liquid phase due to the thickening effect of the polymer. The later is then referred to as a Viscosity-Modifying Admixture (VMA). In the present study, we consider the influence of VMAs on the rheological properties of the material at cement scale level. In particular, the change in the thixotropic properties of the cement paste due to the inclusion of VMA is investigated. It is found that addition of VMA significantly enhances rebuild-up kinetics at rest following shearing at high shear rate. The influence of VMA on the steady state rheological properties is also considered. As reported in the literature, the yield stress is found to monotonically increase with VMA content, while the consistency presents a minimum indicating the existence of an optimum value of the VMA for which the workability of the cement paste is maximum.
Extension of the Poiseuille Formula for Shear-thickening Materials and Application to Self-compacting Concrete
Authors: Feys Dimitri , Verhoeven Ronny , De Schutter Geert 
Published: June 2019

Abstract
In practice, while placing concrete in a formwork by pumping, the pressure generated by the pump is not controlled. In order to enhance the safety on the worksite, and in view of the current economic and ecologic arguments, it would be useful to dispose of an equation able to predict pressure losses based on the rheological properties of the concrete and the pipe configuration. This paper describes the derivation of an extended version of the Poiseuille formula, for shear-thickening materials with a yields stress, described by the modified Bingham equation. This formula is applied to flow-tests with self-compacting concrete. The results prove the applicability of this extended Poiseuille formula, showing that the flow is occurring in laminar regime, with no significant wall slip.
Pure Material Instability and the Concept of Yield Stress
Authors: Balan Corneliu 
Published: June 2019

Abstract
The paper is concerned with the rheological study of gels, complex materials which are characterised by an internal network structure developed in viscous liquids. This category of materials exhibits in viscometric motion a yield state at a critical value of the applied shear stress. The yield shear stress defines the plateau behaviour in the steady flow curve. The creeping experiments and the dynamics of the Oldroyd’s 3 constants model put in evidence the connection between the loss of stability of the network structure and the coexisting strain rates at a constant shear stress. The correlation between theory, numerical simulations and experiments are established. All the results are qualitatively consistent with the statement that the concept of yield stress is ’natural defined‘ in the context of the pure material (structural) instability (i.e. instability at zero Reynolds number) of constitutive relations with non-monotone flow curve.
Computational Rheology with Integral Constitutive Equations
Authors: Mitsoulis Evan 
Published: June 2019

AbstractComputational rheology deals with the formulation and solution of constitutive equations for non-Newtonian materials. From these the emphasis is put on polymeric materials, which exhibit both viscous and elastic behaviour in flow and deformation. These materials are often called viscoelastic materials. Polymer solutions and melts (e.g. commercial plastics and rubber) are good examples of viscoelastic materials. Their processing under continuous (e.g. extrusion) or batch (e.g. injection molding) operations is the main occupation of the plastics and rubber industries, but the corresponding modelling and numerical simulation is a difficult task and a relatively recent undertaking.The present work reviews modelling aspects of viscoelasticity and shows how the complex rheology of these materials is best captured through integral constitutive equations with a spectrum of relaxation times. Using such constitutive equations and the Finite Element Method (FEM), the solution of some benchmark problems of rheology becomes feasible. Examples will be shown from the flow of polymer melts and solutions in a 4:1 axisymmetric contraction encountered in standard capillary rheometry, as well as the flow around a sphere falling in a cylindrical tube. The emphasis will be on demonstrating the flow patterns via streamlines and predicting such viscoelastic phenomena as vortex growth, extrudate swell, and reduction of the drag coefficient, which are of particular interest to the rheological community as test cases of computational results.
A Rheo-optical Investigation into the Viscoelastic Moduli of Acidified Milk Gel
Authors: Arikainen E. O. , Earnshaw J. C. , Wehling A. , Waghorne E. 
Published: June 2019

AbstractDiffusing wave spectroscopy (DWS) in the backscattering geometry was employed to observe the evolution of the intensity correlation function during the acidification of skimmed milk by gluconic-δ-lactone (GDL). At the stage when the formation of casein particle gel is largely complete the correlation function at shorter decay times reveals the local structural arrest of the casein micelles, whereas at longer delay times it illustrates the hindered slow motion of casein micelle aggregates. We use the principles of the approach suggested by Mason, Gang and Weitz, linking the optically measured mean square displacement, <Δr2(t)>, of the microscopic particles in a dense colloid to its viscoelastic properties, to provide an estimate of the frequency dependent viscoelastic modulus of the acidified milk gel (AMG). We compare the viscoelastic moduli measured by the conventional mechanical rheometry with the optically measured ones. The results of the two different experimental methods are found to be in reasonable agreement.