1,795 research outputs found
Contribuição para o estudo da incorporação de materiais poliméricos em membranas betuminosas
A realização deste trabalho inseriu-se na contribuição para o estudo da incorporação de novos materiais poliméricos em membranas betuminosas, mais concretamente na modificação de misturas betuminosas. Para o efeito, foram sintetizados novos poliésteres polióis semelhantes estruturalmente, mas com diferentes pesos moleculares, baseados na utilização de ácidos diméricos de fonte renovável (tall-oil), que serviram de suporte para a produção de prepolímeros de isocianato para a modificação de betumes. A caracterização dos póliesteres polióis e dos polímeros produzidos foi realizada através de espectroscopia de infravermelhos.
Ensaios de engenharia e qualidade, especificados para misturas betuminosas, foram realizados a diversos betumes convencionais e modificados, nos laboratórios industriais das empresas Imperalum e Probigalp como parte integrante no conhecimento dos procedimentos para este tipo de ensaios, nomeadamente o ensaio de penetração, ponto de amolecimento, viscosidade cinemática e dinâmica, apoiando igualmente um estudo de reprodutibilidade inter-laboratorial.
Betumes 160/220 previamente modificados com teores de 1% e 3% de prepolímeros reactivos e, modificados com APP e SBS, foram caracterizados reologicamente a várias temperaturas na zona de viscoelasticidade linear. Os ensaios foram realizados em regime dinâmico através do varrimento em frequência a várias temperaturas. Pela análise dos resultados obtidos, concluiu-se que as modificações consideradas aumentam o carácter elástico dos betumes, confirmado pelo aumento do módulo elástico (G’(ω)).
Os betumes modificados com teores de 1% de prepolímeros foram caracterizados microestruturalmente através de microscopia de força atómica. As imagens topográficas obtidas confirmam a existência de três fases distintas, designadamente a fase catana, perifase e parafase. A avaliação das proporções de cada fase revelou dependências entre a estrutura dos modificadores e a alteração efectiva da microestrutura dos betumes
Place Change and Identity Processes.
This study intents to examine the relationship between place
change and identity process, using Breakwell’s model (1986,
1992) as framework. In the context of a process of imposed
relocation in an old neighbourhood in Lisbon, two groups of
residents were studied in two different moments along the
relocation process. These two groups differ in terms of their choice
of relocation. The generic hypothesis of the study is that relocation,
and the residents’ choice changes the relation of the people with
the space, the social relationships, and it has also an impact in the
resident’s identity. The results show that the relocation process
threats the identity principles in the two groups, but in different
ways, depending of the residential choice, and also had impact in
the social relationships and in the relation of the people with the
space. As other studies (e.g.: Twigger-Ross and Uzzell, 1996;
Speller, Lyons, and Twigger-Ross, 2002) this research underlines
the relationship between changes in physical environment and
identity, in the context of residential environment
Urban neighbourhoods and intergroup relations: The importance of place identity
The aim of this paper is to bring the concept of place identity into the context of intergroup relationships
in urban place, using the social identity approach. A field study was conducted in four adjacent neighbourhoods
in the city of Lisbon, in order to explore the influence of place identity on the perception of
the participants’ own neighbourhood and its residents (in-group) and of the other neighbourhoods and
their residents (out-groups). The results showed that place identity was highly correlated with neighbourhood
satisfaction, relevant out-group differentiation, and favouritism to the in-group and depreciation
of the relevant out-group. The results also enabled the identification of three types of possible
relationships between the groups: a relevant out-group for comparison, an idealized reference group for
approximation, and a devaluated group for avoidance. Moreover, in this study, we extend the predictions
of SIA to the comprehension of specific distance estimation distortion patterns
Identification with the neighborhood: Discrimination and neighborhood size
This paper analyzes the impact of a geographical social grouping
(neighborhood) and its relative perceived size in the spontaneous
group’s identiication level and place satisfaction, as well as the
intensity of and motives for discrimination against inhabitants
of other places. Two studies are presented: an experimental one
using the minimal group categorization paradigm and an onsite
investigation of a city neighborhood. Consistent with the predictions,
the results showed that smaller neighborhoods reported higher
identiication and satisfaction with the place of residence, as well
as higher discrimination of other neighborhoods. In line with the
optimal distinctiveness theory (ODT), the indings showed that the
motivation for discrimination varies as a function of the in-group size.
Thus, the members of larger groups discriminate by increasing the
diferentiation between the in-group and the out-group, whereas
the members of smaller groups increased the value of the in-group.
Furthermore, the results were consistent with a social identity theory
and ODT explanation of diverse research that shows the non-trivial
nature of geographical bounded social grouping and its importance
in a diverse set of contexts and its impact in inter-neighborhood
relationships
Lugar de residência: uma fonte de informação importante para a formação de impressões
Resumo
No estudo da percepção dos grupos podemos distinguir grupos que pelas suas características são percebidos como tendo mais unidade e coerência (entitatividade) do que outros, o que tem implicações no modo como organizamos a informação e formamos impressões sobre os grupos (Hamilton e Sherman, 1996). Assim tendemos a usar mais um processamento integrativo com os grupos que percebemos com grande entitatividade do que com os que percebemos com baixa entitatividade. (e.g.: MacConnell et al.,1997; Susskind et al., 1999). Reconhecido que este conceito pode ser aplicado aos lugares e aos residentes desses lugares (Bernardo & Palma-Oliveira, 2008), realizamos um estudo de laboratório com 162 sujeitos em que testamos o efeito da entitatividade de dois bairros na formação de impressões sobre os seus residentes. Os resultados mostraram que os inquiridos faziam um processamento mais integrativo da informação e mais inferências disposicionais em relação aos residentes de bairros percebidos com maior unidade do que aos bairros percebidos com menor unidade. Estes resultados têm implicações importantes em termos de design urbano
Why do people fail to act? Situational barriers and constraints on ecological behavior
The lack of success in dealing with the inconsistency between positive attitudes and ecological behaviors, and in explaining why people fail to act pro-environmentally is still widespread in practice and research. In our view, this has to do with three main reasons: 1) A positivity fallacy - the belief shared by many researchers and practitioners that as long as people have the right (or positive) attitudes, intentions, skills, information, etc., the right pro-ecological action should follow; thus, they disregard the importance of negative determinants in explaining the attitude-behavior inconsistency. 2) Lack of a psychological level of explanation; even when negative determinants are considered, the psychological explanation is often disregarded or incompletely identified, with most of the factors identified being socio-economical, or urban planning and architectural, etc. However, factors explaining why people fail to act can also be viewed within a psychological level of explanation, with behavior considered to be the result of an interaction between contextual variables and psychological processes. 3) Underestimation of the unconscious processes influence; contextual effects on behavior can be mediated not only by conscious perception but also by cognitive processes of which people are not aware of. Given these reasons, a model of psychological barriers and constraints is proposed (DN-Work model; “Didn’t work”) trying to integrate negative determinants within a psychological explanatory model of pro-ecological behavior. This model aims to represent a process view regarding how a conflict between pro-ecological and anti-ecological behavioral goals can be produced, given the presence of two types of barriers and constraints: a) perceived barriers and constraints, and b) unconscious barriers and constraints. We briefly present two studies based on this model. These studies address habit accessibility as an unconscious behavioral barrier on ecological decisions to buy organic products, mediated by the effect of behavioral-goals activation from the situation
Dynamic mental representations of habitual behaviours: Food choice on a web-based environment
Aim:
Rather
than
being
rigid,
habitual
behaviours
may
be
determined
by
dynamic
mental
representations
that
can
adapt
to
context
changes.
This
adaptive
potential
may
result
from
particular
conditions
dependent
on
the
interaction
between
two
sources
of
mental
constructs
activation:
perceived
context
applicability
and
cognitive
accessibility
.
Method:
T
wo
web-shopping
simulations
of
fering
the
choice
between
habitually
chosen
and
non-habitually
chosen
food
products
were
presented
to
participants.
This
considered
two
choice
contexts
dif
fering
in
the
habitual
behaviour
perceived
applicability
(low
vs.
high)
and
a
measure
of
habitual
behaviour
chronicity
.
Results:
Study
1
demonstrated
a
perceived
applicability
ef
fect,
with
more
habitual
(non-organic)
than
non-habitual
(organic)
food
products
chosen
in
a
high
perceived
applicability
(familiar)
than
in
a
low
perceived
applicability
(new)
context.
The
adaptive
potential
of
habitual
behaviour
was
evident
in
the
habitual
products
choice
consistency
across
three
successive
choices,
despite
the
decrease
in
perceived
applicability
.
Study
2
evidenced
the
adaptive
potential
in
strong
habitual
behaviour
participants
–
high
chronic
accessibility
–
who
chose
a
habitual
product
(milk)
more
than
a
non-habitual
product
(orange
juice),
even
when
perceived
applicability
was
reduced
(new
context).
Conclusion:
Results
portray
consumers
as
adaptive
decision
makers
that
can
flexibly
cope
with
changes
in
their
(inner
and
outer)
choice
contexts.Fundação para a Ciência e a Tecnologia (FCT
Educating for earthquake science and risk in a tectonically slowly deforming region
Over the past decade, scientists have been called to participate more actively in public education and outreach (E&O). This is particularly true in fields of significant societal impact, such as earthquake science. Local earthquake risk culture plays a role in the way that the public engages in educational efforts. In this article, we describe an adapted E&O program for earthquake science and risk. The program is tailored for a region of slow tectonic deformation, where large earthquakes are extreme events that occur with long return periods. The adapted program has two main goals: (1) to increase the awareness and preparedness of the population to earthquake and related risks (tsunami, liquefaction, fires, etc.), and (2) to increase the quality of earthquake science education, so as to attract talented students to geosciences. Our integrated program relies on activities tuned for different population groups who have different interests and abilities, namely young children, teenagers, young adults, and professionals
Combined effects of irrigation management and nitrogen fertilization on soft wheat productive responses under Mediterranean conditions
Wheat yield responses to water and nitrogen vary widely among different environments and they can be shifted due to technological, environmental, or economic factors. In regions with a Mediterranean-type climate, the balance between the key climate variables and the most critical stages of wheat grow implies that the success of the crop depends to a very large degree on the knowledge of proper water management combined with suitable fertilization strategies. For this purpose, we studied the productive responses of soft wheat to the interactive effects of irrigation and nitrogen (N) fertilization. Two trials were carried out during 2016/2017 in Beja (Southern Portugal). In both experiments, wheat responses were assessed under two water supply regimes: D1 (100% of full irrigation throughout the cycle) and D2 (100% of full irrigation at four stages: stem extension; booting; heading; grain filling). In the first trial, 165 kg of slow-release and stabilized N fertilizers were applied through 6 splitting treatments, five of them (A1 to A5) with a slow-release N fertilizer (A1 – 100% at sowing; A2 – 50% at sowing and 50% at booting; A3 - 50% at sowing, and 25% at stem extension and at heading; A4 – 75% at sowing and 25% at booting; A5 - 75% at sowing and 25% at stem extension) and another one (A6) with a stabilized N fertilizer 100% applied at sowing. In the second trial, 165 kg of conventional N fertilizer was applied through 5 splitting treatments (A1 – 33% at sowing, at tillering and at stem extension; A2 – 25% at sowing, at tillering, at stem extension and at heading; A3 - 25% at sowing, at tillering, at stem extension and at booting; A4 – 50% at tillering and 25% at booting and at heading; A5 - 50% at sowing and 25% at stem extension and at booting). In the first trial, only the number of heads per square meter showed significant influence of the irrigation regime, the highest values being registered in the D1 treatment. In the trial with conventional fertilizer, significantly higher yields and weights of 1000 grains were obtained in the D1 irrigation treatment. Significant effects of split N fertilizer application occurred only in the first trial: yield was higher in the A5 treatment, showing that early N applications with this type of fertilizers do not compromise N availability throughout the wheat grow cycle and therefore the grain production; grain protein content was higher in the A2 treatment, indicating the importance of N availability at the booting stage in order to obtain grains with desirable quality traits
Influência da Gestão da Rega e da Fertilização Azotada na Produção de Trigo mole (variedade ‘antequera’)
Na última década tem-se verificado uma diminuição da produção de trigo mole em Portugal. A sustentabilidade económica e ambiental desta cultura passa pelo uso racional da rega, da fertilização e dos tratamentos fitossanitários. Para isso é fundamental conhecer a eficiência do uso de todos os fatores de produção de forma a rentabilizar a atividade e diminuir as perdas. De entre os factores de produção, destacam-se a água e o azoto, já que eles permitem uma maior mobilização/absorção dos nutrientes no solo e a obtenção de elevadas produções de grão com elevada qualidade tecnológica. Neste contexto, pretende-se garantir o máximo potencial genético de produção e a elevada qualidade para moagem, através da optimização da gestão de rega e da fertilização azotada, melhorando a eficiência de uso destes fatores.
Neste estudo foram avaliados os efeitos de duas estratégias de rega: R1 - rega com 100 % evapotranspiração cultural (ETc) e R2 - rega com 100 % ETc nas fases críticas de desenvolvimento da cultura, e de cinco estratégias de fraccionamento/época de aplicação de fertilizantes azotados clássicos (C) e de libertação gradual (EEF) na produção e qualidade do grão de trigo, variedade ‘Antequera’.
Nos ensaios com fertilizantes EEF, apesar de se obter uma produção mais elevada na modalidade de rega R1 (4594 kg/ha), as produções nas duas estratégias de rega não se diferenciam estatisticamente. Nos ensaios com fertilizantes C, o rendimento na modalidade R1 foi superior (5614 kg/ha). Quanto à estratégia de fertilização azotada, observa-se, na utilização de EEF, que a produção de trigo é superior (4564 kg/ha) com um fraccionamento de azoto de 75 % na sementeira e 25 % no encanamento. Constata-se que uma maior disponibilidade de azoto na fase de emborrachamento permite a obtenção de maior teor de proteína no grão (17.38 %). As estratégias de aplicação de fertilizantes C, em regadio, não têm efeito estatisticamente significativo em qualquer dos parâmetros produtivos avaliados
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