Structure-property relationships in polymer nanocomposites

Tese de Doutoramento em Ciência e Engenharia de Polímeros e Compósitos

Structure-properties relationships in thermoplastic polyurethane elastomer nanocomposites: Interactions between polymer phases and nanofillers

Polyurethane thermoplastic elastomer (TPU) nanocomposites were prepared by the incorporation of 1 wt% of high-structured carbon black (HSCB), carbon nanofibers (CNF), nanosilica (NS) and nanoclays (NC), following a proper high-shear blending procedure. The TPU nanofilled mechanical properties and morphology was assessed. The nanofillers interact mainly with the TPU hard segments (HS) domains, determining their glass transition temperature, and increasing their melting temperature and enthalpy. A significant improvement upon the modulus, sustained stress levels and deformation capabilities is evidenced. The relationships between the morphology and the nanofilled TPU properties are established, evidencing the role of HS domains on the mechanical response, regardless the nanofiller type.

Size effects on the magnetoelectric response on PVDF/Vitrovac 4040 laminate composites

Tri-layered and bi-layered magnetoelectric (ME) flexible composite structures of varying geometries and sizes consisting on magnetostrictive Vitrovac and piezoelectric poly(vinylidene fluoride) (PVDF) layers were fabricated by direct bonding. From the ME measurements it was determined that tri-layered composites structures (magnetostrictive-piezoelectric-magnetostrictive type), show a higher ME response (75 V.cm-1.Oe-1) than the bi-layer structure (66 V.cm 1.Oe-1). The ME voltage coefficient decreased with increasing longitudinal size aspect ratio between PVDF and Vitrovac layers (from 1.1 to 4.3), being observed a maximum ME voltage coefficient of 66 V.cm-1.Oe-1. It was also observed that the composite with the lowest transversal aspect ratio between PVDF and Vitrovac layers resulted in better ME performance than the structures with higher transversal size aspect ratios. It was further determined an intimate relation between the Vitrovac PVDF Area Area ratio and the ME response of the composites. When such ratio values approach 1, the ME response is the largest. Additionally the ME output value and magnetic field response was controlled by changing the number of Vitrovac layers, which allows the development of magnetic sensors and energy harvesting devices.

On the length of bank-firm relationships: an empirical application to a major French bank

NIPE - WP 01/ 2016

Single-function approach to calibrating whatman n.º 42 filter paper based on suction versus water content relationships

Several suction–water-content (s-w) calibrations for the filter paper method (FPM) used for soil-suction measurement have been published. Most of the calibrations involve a bilinear function (i.e., two different equations) with an inflection point occurring at 60 kPa

Colaboração em inovação: parceiros ou concorrentes?

Dissertação de mestrado em Economia Industrial e da Empresa

Food Structure Design: Innovation in food structure-properties relationships

This Special Issue gathers selected contributions from the 1st Congress on Food Structure Design, covering most of the topics described above.

Assessing the suitability of the minimum capture size and protection regimes in the gooseneck barnacle shellfishery

The suitability of a total-length-based, minimum capture-size and different protection regimes was investigated for the gooseneck barnacle Pollicipes pollicipes shellfishery in N Spain. For this analysis, individuals that were collected from 10 sites under different fishery protection regimes (permanently open, seasonally closed, and permanently closed) were used. First, we applied a non-parametric regression model to explore the relationship between the capitulum Rostro-Tergum (RT) size and the Total Length (TL). Important heteroskedastic disturbances were detected for this relationship, demon- strating a high variability of TL with respect to RT. This result substantiates the unsuitability of a TL-based minimum size by means of a mathematical model. Due to these disturbances, an alternative growth- based minimum capture size of 26.3 mm RT (23 mm RC) was estimated using the first derivative of a Kernel-based non-parametric regression model for the relationship between RT and dry weight. For this purpose, data from the permanently protected area were used to avoid bias due to the fishery. Second, the size-frequency distribution similarity was computed using a MDS analysis for the studied sites to evaluate the effectiveness of the protection regimes. The results of this analysis indicated a positive effect of the permanent protection, while the effect of the seasonal closure was not detected. This result needs to be interpreted with caution because the current harvesting based on a potentially unsuitable mini- mum capture size may dampen the efficacy of the seasonal protection regime.

A revolução fashion: os blogs como instrumentos de consolidação da identidade plus size

Dissertação de mestrado em Comunicação, Arte e Cultura

Study of validation of the Portuguese version of the inventory «Experiences in Close Relationships»

The Experiences in Close Relationships Inventory permits to evaluate attachment in close relationships during adulthood based on two dimensions able to be present in this kind of relationships: the avoidance of proximity and the anxiety related with to abandonment. It is a self-report 7- points likert scale composed by 36 items. The Portuguese version was administered to a sample of 551 university students (60% female), the majority with ages between 19 and 24 years old (88%) in a dating relationship (86%). The principal components analysis with oblimin rotation was performed. The total scale has good internal consistency (α=.86), as also has the 2 sub-scales: anxiety (α=.86) and avoidance (α=.88). The two dimensions evaluated are significantly correlated with socio-demographics, relational characteristics (jealousy, relationship distress, and compromise), wishes (enmeshment versus differentiation) and fears (abandonment versus control) related to attitudes in significant relationships, which testify the construct validity of the instrument. The results obtained are coherent with the original version and other ECR‘s adaptations. Practitioners and researchers in the context of clinical psychology and related areas have now at their disposal the Portuguese version of the ECR inventory, which has shown its very high usefulness in the study of close relationships, and specifically attachment in adulthood.

Massage therapy reduces pain in pregnant women, alleviates prenatal depression in both parents and improves their relationships

Prenatally depressed women (N=47) were randomly assigned to a group that received massage twice weekly from their partners from 20 weeks gestation until the end of pregnancy or a control group. Self-reported leg pain, back pain, depression, anxiety and anger decreased more for the massaged pregnant women than for the control group women. In addition, the partners who massaged the pregnant women versus the control group partners reported less depressed mood, anxiety and anger across the course of the massage therapy period. Finally, scores on a relationship questionnaire improved more for both the women and the partners in the massage group. These data suggest that not only mood states but also relationships improve mutually when depressed pregnant women are massaged by their partners.

Partner relationships during pregnancy in anxious and depressed women and men

To assess anxiety, depression and relationship satisfaction in both women and men during pregnancy, the State Anxiety Inventory (STAI), The Center for Epidemiological Studies-Depression Scale (CES-D) and The Relationship Questionnaire (RQ) were administered during the second trimester to a sample of 59 pregnant women and their partners. Anxious pregnant women rated their relationships as less positive. Depressed pregnant women also rated their relationships as less positive. The women’s anxiety scores were predictive of their positive and negative relationship scores. The women and their partners’ negative relationship scores were also predictive of each others’ negative relationship scores. These results highlight the importance of targeting anxiety as well as depression, and pregnant women as well as their partners in prenatal intervention programs.

Factores de risco de abuso no relacionamento íntimo: Estudo de validação da versão portuguesa do questionário “Personal and Relationships Profile”

O presente artigo trata do estudo das características psicométricas da versão portuguesa do questionário “Personal and Relationships Profile" (PRP, Straus, Hamby, Boney-McCoy, & Sugarman, 1999). Este instrumento destina-se a avaliar os principais factores relacionados com a ocorrência de abuso no relacionamento com o companheiro; integra 21 sub-escalas substantivas e uma sub-escala de desejabilidade social. Foram participantes 551 estudantes universitários (60.3% do sexo feminino), na sua maioria com idades compreendidas entre os 19 e os 25 anos e com uma relação do tipo namoro. O questionário apresenta elevada consistência interna (α=.90), e as sub-escalas têm valores de alpha de Cronbach compreendidos entre .50 e .84. Confirma-se também a validade externa dado que um elevado número de sub-escalas do PRP, se encontra significativamente correlacionado com a escala de abuso físico sem sequelas (CT52). Os resultados obtidos confirmam a validade da versão portuguesa do questionário PRP, possibilitando a investigadores e práticos no âmbito das relações maritais um instrumento de screening para sinalização, aprofundamento e orientação das linhas de acção específicas no tratamento e/ou investigação dos principais factores associados à violência conjugal.

From perfect strangers to research partners: a study of relationships, resource sharing and perceived benefits within R&D cooperation networks

Doctoral thesis in Marketing and Strategy.

In-line rheo-optical microstructural characterization of complex polymer systems

Tese de Doutoramento em Ciência e Engenharia de Polímeros e Compósitos.