Nous présentons dans ce travail une étude approfondie de la rhéologie à l'état fondu de composites très chargés en particules inorganiques. Les systèmes modèles étudiés sont composés de particules de ferrites ou de fibres de verre dispersées dans une matrice polypropylène. Le comportement rhéologique linéaire et non-linéaire ainsi que la morphologie des composants du mélange ont été étudiés. Sous différentes conditions d'écoulement, nous avons pu mettre en évidence la relation étroite qu'il existe entre la microstructure du matériau, sa formulation et ses propriétés rhéologiques. Nous avons ainsi évalué les principaux paramètres liés à la charge (e.g., distribution de taille, facteur de forme, chimie de surface) sur la viscosité du mélange. Ces travaux ont montré que l'ajout de charges dans une matrice thermoplastique change fondamentalement la rhéologie linéaire et non-linéaire du mélange. Sous écoulement dynamique, nous avons pu quantifier les interactions entre les charges (force de contact) et charges-polymère. D'une part, les systèmes ferrites/polypropylène ont montré une forte structuration dans le temps, ce qui se traduit par un comportement type réseaux à très faibles déformation. D'autre part, les systèmes fibres/polypropylène ont montré qu'un facteur de forme plus élevé et de meilleures interactions fibre-fibre favorisaient la création du réseau de particules. Sous écoulement permanent, les phénomènes non-linéaires ont été également étudiés. Nous n'avons pas mis en évidence de phénomènes de glissement pour l'ensemble de ces systèmes. Plus particulièrement, le système ferrites/polypropylène a montré une atténuation du comportement pseudo-plastique à haute vitesse de cisaillement. Ainsi, ce travail expérimental a contribué à la compréhension des propriétés d'écoulement de ces systèmes complexes / We present in this work a complete study of the melt rheological behavior of highly filled polymers. We study the rheological behavior of two model systems, ferrite particles and short-glass fibers dispersed in polypropylene. We investigate the structural features of such complex materials by linear and non-linear rheological behavior. Under different flow conditions, we show the close relationship between the variation in the microstructure, the formulation and the flow properties. We evaluate the effect of the main parameters related to the filler (e.g., particle size distribution, aspect ratio, surface chemistry) on the viscosity of the mixture. This work shows that the addition of fillers fundamentally changes the linear and non-linear viscoelasticity of the molten composite. Under dynamic flow, we are able to quantify the particle-particle and matrix-particle interactions. Therefore, we study the creation of the filler network with increasing the particulate phase. On the one hand, ferrite/polypropylene systems presented a network structure that evolves over time which manifest by a solid-like behavior accentuation at very low deformations. On the other hand, fibers/polypropylene composites showed that the higher the aspect ratio and the interparticle interactions, the higher is the probability to create a network structure. Under steady state flow, the non-linear behavior is studied. Wall slip effects were found to be negligible under the flow conditions studied in this work. In particular, ferrite/polypropylene showed an attenuation of the shear-thinning behavior at low shear rates. Thus, this experimental work has contributed to the understanding of the flow properties of these complex materials

Tesis por compendio / "Development of polylactic acid (PLA)-derived formulations by plasticization and additives from renewable resources" The main objective of this doctoral thesis is the study, development and characterization of biodegradable or biocompatible materials from poly(lactic acid) (PLA) with improved properties for uses in several sectors such as food packaging, medical sector, etc. In order to modify the ductility and the stiffness of PLA, with the subsequent effects on its potential uses in different sectors, different fillers and/or additives were incorporated to PLA formulations by extrusion. Several plasticizers derived from vegetable oils and fatty acids were used; particularly, an epoxidized plasticizer derived from stearic acid (octyl epoxy stearate - OES) and a maleinized linseed oil - MLO were used. Another strategy that has been used in this research has focused on the development of binary blends with other polymers with increased ductility such as polycaprolactone (PCL) and thermoplastic starch (TPS). Finally, incorporation of several biocompatible/resorbable fillers derived from calcium orthophosphate (Ca3(PO4)2) such as ß-tricalcium phosphate (ß-TCP) and hydroxyapatite (HA), was carried out to widen the potential of these PLA-based materials in medical applications. / "Desarrollo de formulaciones derivadas de ácido poliláctico (PLA), mediante plastificación e incorporación de aditivos de origen natural" El objetivo principal de esta tesis doctoral es el estudio, desarrollo y caracterización de materiales biodegradables o biocompatibles de ácido poliláctico (PLA) con propiedades mejoradas para su aplicación en diversos sectores como el envasado de alimentos, sector médico, etc. Para modificar la ductilidad o rigidez del PLA y con ello su aptitud en los distintos campos, se lleva a cabo un estudio de la incorporación de diferentes cargas o aditivos, mediante mezclado por extrusión. Se han utilizado plastificantes derivados de aceites vegetales y ácidos grasos; en particular, un plastificante epoxidado derivado del ácido esteárico (epoxi estearato de octilo - OES) y un derivado maleinizado de aceite de linaza - MLO. Otra de las estrategias que se han abordado se ha centrado en el desarrollo de mezclas binarias con otros biopolímeros con mayor ductilidad como la policaprolactona (PCL) y el almidón termoplástico (TPS). Finalmente, se ha llevado a cabo la incorporación de cargas biocompatibles tipo ortofosfato cálcico (Ca3(PO4)2) como el ß-fosfato tricálcico (ß-TCP) y la hidroxiapatita (HA) para ampliar el potencial de estos materiales basados en PLA en el sector médico. / "Desenvolupament de formulacions derivades d'àcid polilàctic (PLA), mitjançant plastificació i incorporació d'additius d'origen natural" L'objectiu principal d'aquesta tesi doctoral és l'estudi, desenvolupament i caracterització de materials biodegradables i biocompatibles d'àcid polilàctic (PLA) amb propietats millorades per a la seua aplicació en diversos sectors com ara l'envasat d'aliments, sector mèdic, etc. Per tal de modificar la ductilitat o rigidesa del PLA, i amb això, la seua aptitud en els esmentats camps, s'ha fet un estudi de la incorporació de diferents càrregues o additius, mitjançant mesclat per extrusió. S'han utilitzat plastificants derivats d'olis vegetals i àcids grassos; en particular, un plastificant epoxidat derivat de l'àcid esteàric (epoxi estearat d'octil - OES) i un derivat maleinitzat d'oli llinós - MLO. Una altra estratègia que s'ha seguit s'ha centrat en el desenvolupament de mescles binàries amb altres polímers amb major ductilitat com ara la policaprolactona (PCL) i el midó termoplàstic (TPS). Finalment, s'ha dut a terme la incorporació de càrregues biocompatibles de tipus ortofosfat càlcic (Ca3(PO4)2) com ara el ß-fosfat tricàlcic (ß-TCP) i la hidroxiapatita (HA) per tal d'ampliar el potencial d'aquests materials basats en PLA al sector mèdic. / Ferri Azor, JM. (2017). Desarrollo de formulaciones derivadas de ácido poliláctico (PLA), mediante plastificación e incorporación de aditivos de origen natural [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86166 / TESIS / Premios Extraordinarios de tesis doctorales / Compendio

Yes / Ultra-high performance concrete (UHPC) is an innovative cementitious composite, that has been widely applied in numerous structural projects because of its superior mechanical properties and durability. However, ensuring the safety of UHPC structures necessitates an urgent need for technology to continuously monitor and evaluate their condition during their extended periods of service. Self-sensing ultra-high performance concrete (SSUHPC) extends the functionality of UHPC system by integrating conductive fillers into the UHPC matrix, allowing it to address above demands with great potential and superiority. By measuring and analyzing the relationship between fraction change in resistivity (FCR) and external stimulates (force, stress, strain), SSUHPC can effectively monitor the crack initiation and propagation as well as damage events in UHPC structures, thus offering a promising pathway for structural health monitoring (SHM). Research on SSUHPC has attracted substantial interests from both academic and engineering practitioners in recent years, this paper aims to provide a comprehensive review on the state of the art of SSUHPC. It offers a detailed overview of material composition, mechanical properties and self-sensing capabilities, and the underlying mechanisms involved of SSUHPC with various functional fillers. Furthermore, based on the recent advancements in SSUHPC technology, the paper concludes that SSUHPC has superior self-sensing performance under tensile load but poor self-sensing performance under compressive load. The mechanical and self-sensing properties of UHPC are substantially dependent on the type and dosage of functional fillers. In addition, the practical engineering SHM application of SSUHPC, particularly in the context of large-scale structure, is met with certain challenges, such as environment effects on the response of SSUHPC. Therefore, it still requires further extensive investigation and empirical validation to bridge the gap between laboratory research and real engineering application of SSUHPC. / The full-text of this article will be released for public view at the end of the publisher embargo on 28 Dec 2024.

M.S.

This study focuses on addressing inefficiencies in packaging processes at Spaljisten AB caused by extensive filler usage, aiming to enhance efficiency and reduce environmental impact. After a thorough review of existing literature and packaging techniques, four alternative packaging models were evaluated through SWOT analyses. Model 3, utilizing tabs to fold cardboard edges for product protection, emerged as the most promising solution, balancing efficiency, sustainability, and technical feasibility by significantly reducing fillers dependency and waste. Further research is suggested to explore scalability and long-term sustainability, ensuring Spaljisten AB meets evolving market demands and consumer expectations for sustainability.

Hyaluronan (HA) is a substance that is commonly used in biomedical applications in the form of hydrogels. One of these biomedical applications is dermatological fillers where HA is cross-linked with 1,4-Butanediol diglycidyl ether (BDDE) to reduce its rapid turnover within tissue. The filler gives a volumetric effect that can fill out wrinkles. This literature study was conducted in collaboration with Galderma to determine if there is research that explores additives to HA hydrogels that give both volumetric and biological effects when applied as filler. Biological effects that improve the skin's appearance and complexion such as a rejuvenation of the skin was preferable. Both polynucleotides and mannitol show great potential to act as additives in injectable hyaluronan hydrogels.  The main effect of polynucleotides (PN) added in hydrogels is that it is collagen stimulating and provides a more natural tissue regeneration. Rheological properties of the filler change with the addition of PN, where elasticity, viscosity and viscoelasticity have been shown to increase. PNs show no toxicity and are considered safe to inject. The study of mannitol has shown that it does not give a volumetric effect after the injected hydrogel has been broken down. What mannitol can help with, is to prolong the life of the hydrogel and reduce the swelling that is a common side effect after an injection. In addition to this, mannitol is a safe substance to inject.

Atualmente o maior impacto ambiental do concreto como material de construção origina-se das emissões de CO2 durante a produção do cimento. Uma das alternativas atualmente utilizadas para minimizar este impacto, é a utilização de adições minerais como substituição ao cimento. Entre as diferentes adições utilizadas, o uso de fíler calcário parece ser uma alternativa interessante para melhorar a sustentabilidade do uso do concreto na construção. Consequentemente, o presente estudo foca a análise do impacto da substituição do cimento por fílers de origem calcária (dolomita) no comportamento do concreto em estado fresco e endurecido, especialmente focando-se numa avaliação reológica e na retração por secagem do material. Para tal fim, foram formulados três microconcretos com teores de fíler calcário de 80%, 60% e 20% em relação ao peso dos finos totais (cimento mais fíler calcário). O teor de finos totais e de água foram mantidos constantes para todas as formulações resultando em misturas com similar volume de pasta. O comportamento reológico das misturas foi avaliado num reômetro de movimento planetário. Foram moldados corpos de prova para caracterização mecânica e acompanhamento da retração por secagem. A porosidade das pastas também foi avaliada usando a porosimetria por intrusão de mercúrio. As propriedades reológicas como a tensão de escoamento e a viscosidade foram influenciadas pelo teor de substituição de cimento por fílers. Maiores volumes de fílers na pasta produziram menores tensões de escoamento e, por consequência, maiores valores de abatimento foram obtidos. No entanto, a viscosidade plástica aumentou com teor de fílers. No estado endurecido, a maior substituição de cimento por fílers diminui a intensidade da retração por secagem devido ao menor teor de cimento na pasta e a modificações na estrutura porosa do material. Os resultados experimentais da retração foram comparados com os valores obtidos pelos modelos de previsão da retração: ACI 209, CEB-FIP, B3 e GL2000. Observou-se que os modelos superestimam os valores da retração conforme aumenta a substituição de cimento por fílers na pasta. Portanto, esses modelos devem ser calibrados considerando outros fatores, tais como: a quantidade de fíler utilizado em substituição de cimento. Esta consideração poderia otimizar o uso dos modelos em fase de projeto para verificar se os valores da retração esperados estão dentro dos limites normalmente aceitos. / Currently the biggest environmental impact of concrete as a building material originates in CO2 emissions during the production of cement. For this reason, one of the alternatives currently used to reduce these emissions is the use of mineral additions as cement replacement. Among the different additions used, the use of limestone fillers to replace cement appears to be an interesting alternative for improve the sustainability of the concrete used in construction. Consequently, this study focuses on the analysis of the impact of the replacement of cement by limestone fillers in fresh and hardened concrete, especially focusing on rheological behavior and shrinkage of the material. To this end, three microconcretos were formulated with fillers limestone content of 80%, 60% and 20% by weight relative to the total fine (limestone fillers and cement). The total content of fine and water were held constant for all formulations resulted in mixtures with similar volume of paste. The rheological behavior of the mixes was evaluated in a planetary motion rheometer. For mechanical characterization and measurement of shrinkage, specimens were molded. The porosity of the pastes was also evaluated using mercury intrusion porosimetry. The rheological properties such as yield stress and viscosity were influenced by the amount of cement that was replaced by fillers. Further filers volumes in the pulp produced smaller flow stress and, consequently, higher allowance values were obtained. Larger volumes of filler in the paste produced lower yield stresses and, consequently, higher slump values were obtained. However, the plastic viscosity increased with filers content. In the hardened condition, the largest cement replacement by limestone fillers reduced the intensity of shrinkage due to the lower content of cement paste and changes in the porous structure of the material. The experimental results of shrinkage were compared with the values obtained by shrinkage prediction models: ACI 209, CEB-FIP, B3 and GL2000. It was observed that the models overestimate the shrinkage values with increasing cement replacement by limestone fillers. Therefore, these models must be calibrated considering other factors such as the amount of fillers used as cement replacement This consideration would optimize the use of these models in the design phase to verify that the values of the expected shrinkage are within the limits normally accepted.

One of the primary objectives of this thesis was to design fiber/filler/polymer structures for newsprint and in the process develop a greater understanding of fiber/filler/ polymer structures. Five different designed structures were created for study. The designed structures were composed of virgin, hydrosulfite bleached, TMP southern pine, Georgian kaolin clay and various polymers. Five filler levels from 0% to 20% were employed with each of these different structures. Numerous physical tests were used to gather data which would help to develop an understanding for the macroscopic properties of the structures. Paper structures were created and data from bulk physical tests and particle based SEM image analyses were compared. Comparisons were made using a statistical method called Principal Component Analysis (PCA) where the data is grouped and reduced to find data correlations not readily apparent in the raw data.

This paper deals with defining and mapping of fillers in the Czech vocabulary. It also analyzes its problematic function in Czech language system. The analysis is divided into two parts- methodology and research. The first part is dedicated to fillers' purpose in the Czech vocabulary and classification of fillers into word classes. It also deals with other linguistic publications on this topic. The research is aiming to analyze certain authentic speeches and to specify the position of fillers in the communication of Czech speakers.

The following essay presents a case study based on participant observation of a group of Swedish secondary school students’ interaction in English. The study focused on what is commonly referred to as communicative competence, or more specifically strategic competence, which represents how language speakers overcome linguistic breakdowns or gaps in their communicative skill. The aim of the study was to better understand how students use linguistic fillers in different situations. By observing students in two different situations, one stressful and one regular conversational situation, it was found that when in a stressful situation, students are more likely to use linguistic fillers in general and also that some students rely on their first language, Swedish, when using linguistic fillers. In this case study, it was found that some students experience difficulties in using English linguistic fillers. Based on these findings, there is a need for teachers to address this problem if students are to develop confidence and skill in using them. For this reason, there is a need for further research on developing and testing different teaching methods on the use of linguistic fillers.   Keywords: communicative competence, EFL, language didactics, linguistic fillers, participant observation, secondary school students, strategic competence.