1,174 research outputs found
Simulação computacional do escoamento do ar no interior de um auditório
Tese de mestrado integrado. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto. 201
Error Probability Mitigation in Quantum Reading using Classical Codes
A general framework describing the statistical discrimination of an ensemble
of quantum channels is given by the name of quantum reading. Several tools can
be applied in quantum reading to reduce the error probability in distinguishing
the ensemble of channels. Classical and quantum codes can be envisioned for
this goal. The aim of this paper is to present a simple but fruitful protocol
for this task using classical error-correcting codes. Three families of codes
are considered: Reed-Solomon codes, BCH codes, and Reed-Muller codes. In
conjunction to the use of codes, we also analyze the role of the receiver. In
particular, heterodyne and Dolinar receivers are taken in consideration. The
encoding and measurement schemes are connected by the probing step. As probe we
consider coherent states. In such simple manner, interesting results are
obtained. As we show, for any fixed rate and code, there is a threshold under
which using codes surpass optimal and sophisticated schemes. However, there are
codes and receiver schemes giving lower thresholds. BCH codes in conjunction
with Dolinar receiver turn out to be the optimal strategy for error mitigation
in the quantum reading task
Desenvolvimento da aplicação Carris para o transporte público de Lisboa
O presente estágio curricular foi realizado no âmbito da Unidade Curricular de Estágio pertencente ao mestrado de Engenharia Informática – Computação Móvel, lecionado na Escola Superior de Tecnologia e Gestão (ESTG), pertencente ao Instituto Politécnico de Leiria (IPLeiria). Este estágio teve como objetivo aplicar os conhecimentos obtidos durante o percurso académico. Foi realizado numa empresa de soluções informáticas, a Tecnologias de Microelectónica (Tecmic). Durante este estágio, foi possível conhecer mais detalhadamente o mundo do mercado de trabalho e foram adquiridas novas competências para a vida profissional. O trabalho realizado foi o resultado de uma necessidade da Tecmic e de um cliente de transportes públicos, a Carris. O trabalho teve como objetivo o desenvolvimento de uma aplicação para dispositivos móveis (Android e iOS) ajustada às necessidades do cliente que fosse o mais intuitiva possível, respeitando a diversificação das idades dos utentes da Carris. Esta aplicação, para além de promover a imagem da Carris, incentiva o uso dos transportes públicos na região de Lisboa. A aplicação permite obter informação detalhada sobre as paragens e as linhas pertencentes à Carris tal como as estimativas de tempo de espera correspondentes às paragens. A aplicação responde à contextualização geográfica do utilizador apresentando as paragens mais próximas de si ou através do planeamento de uma viagem. O trabalho desenvolveu-se segundo as boas práticas de desenvolvimento de software, seguindo as guidelines da Apple e da Google, tendo sido colocado em produção com base nos requisitos, nos testes realizados e na aprovação do cliente. As aplicações Android e iOS ficaram alojadas nas respetivas stores contando até ao momento com um grande número de utilizações e instalações de ambas as plataformas
Maximal exercise testing early after myocardial infarction — better to predict cardiac events?
Interacções entre iões metálicos e surfactantes aniónicos
Tese de doutoramento em Química, na especialidade de Química Macromolecular, apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraO conhecimento do mecanismo e das diferentes propriedades envolvidas nas
interacções entre iões metálicos di- e trivalentes e surfactantes aniónicos revela-se
fundamental, nas áreas que utilizam conjuntamente estas espécies, possibilitando uma
optimização dos processos existentes ou mesmo novas aplicações.
Neste trabalho é estudado o efeito de diferentes surfactantes aniónicos no
comportamento de iões metálicos multivalentes, em solução aquosa. Para tal, foram
utilizados sistemas envolvendo dois tipos de surfactantes aniónicos: sulfatos (dodecil
sulfato de sódio) e carboxilatos (octanoato, decanato e dodecanoato de sódio); e os
seguintes iões metálicos: alumínio(III), crómio(III), lantânio(III), gadolínio(III), cálcio(II)
e chumbo(II). A utilização de dois tipos de surfactantes aniónicos permite aferir acerca
do efeito do grupo iónico dos mesmos no processo de interacção com os iões metálicos. O
facto de serem utilizados surfactantes baseados em carboxilatos, com diferentes
tamanhos de cadeia alquílica, possibilita ainda uma avaliação do efeito hidrofóbico no
processo de interacção. A escolha dos iões metálicos foi realizada de modo a abarcar
distintas propriedades, tais como a valência, densidade de carga, hidratação, e diferentes
áreas de aplicação. A labilidade do ião alumínio, relativamente à perda de moléculas de
água da sua esfera de hidratação primária, quando comparada com o ião crómio, que é
praticamente inerte a esta substituição, é um exemplo das distintas propriedades em
análise. O facto de alguns iões metálicos possuírem interessantes propriedades
magnéticas e espectroscópicas abre também a possibilidade de identificar o efeito dos
surfactantes nas mesmas. A variabilidade das propriedades dos sistemas em estudo
permite identificar a predominância de efeitos no processo de interacção entre iões
metálicos e surfactantes. Os sistemas foram estudados recorrendo a diferentes técnicas experimentais,
tais como: condutibilidade eléctrica, potenciometria (pH e usando eléctrodos selectivos),
espectroscopia de ressonância magnética nuclear (27Al e 139La), turbidimetria,
luminescência e espectrometria de massa por plasma acoplado indutivamente. Os
complexos sólidos resultantes da interacção foram caracterizados através de
espectroscopia no infravermelho por transformada de Fourier (FTIR), ressonância
magnética nuclear (1H e 13C), difracção de raio-X, termogravimetria, calorimetria
diferencial de varrimento e termomicroscopia de luz polarizada.
Através da quantificação de iões metálicos em solução, são propostos modelos
que permitem estimar as constantes de associação relativas à complexação de diferentes
iões metálicos e surfactantes. Nos sistemas em que participa o dodecil sulfato de sódio, é
realizado um estudo termodinâmico ao processo de micelização, identificando o efeito de
distintos iões trivalentes nesse processo.
Com os dados apresentados nesta dissertação pensamos poder contribuir para a
um maior conhecimentos dos factores que limitam ou induzem a interacção entre iões
metálicos e surfactantes aniónicos.The knowledge of the mechanisms and of the different properties involved in the
interactions between di- and trivalent metal ion and anionic surfactants are
fundamental, in areas that use these two species, and can help in process optimization or
even lead to new applications.
In this work, we have studied the effect of different anionic surfactants on the
behaviour of multivalent metal ions in aqueous solution. For this, systems were used
involving two different types of anionic surfactants: sulfates (sodium dodecyl sulfate)
and carboxylates (sodium octanoate, decanoate and dodecanoate), together with the
following metal ions: aluminium(III), chromium(III), lanthanum(III), gadolinium(III),
calcium(II) and lead(II). The two different types of anionic surfactants were used to shed
light on the effect of the ionic group on the interaction process with metal ions. The use
of carboxylate surfactants, with different alkyl chain lengths, makes the evaluation of the
hydrophobic effect in the interaction process possible. Metal ions have been chosen to
encompass different properties, such as valency, charge density, hydration, and the
different application areas. The lability of aluminium ions in terms of the exchange of
coordinated water molecules from the primary coordination sphere, when compared
with chromium, which is practically inert to substitution, is one example of the different
properties in analysis. Interesting magnetic and spectroscopic properties of metal ions
open the possibility of studying their change upon surfactant addition. The variation of
the system properties will lead to the identification of the main effects occurring in the
interaction process between metal ions and surfactants.
Systems were studied by various experimental techniques, such as: electrical
conductivity, potentiometry (pH and ion selective electrodes), nuclear magnetic
resonance spectroscopy (27Al and 139La), turbidity, luminescence and inductively coupled plasma-mass spectrometry. The solid complex resulting from interaction, were
characterized by Fourier-transform infrared (FTIR), nuclear magnetic resonance (1H and
13C), X-ray powder diffraction, thermogravimetry, differential scanning calorimetry and
polarized light thermal microscopy.
Based on the quantification of metal ions in solution, models were proposed to
estimate the association constants for complexation of the different metal ions with
surfactants. A thermodynamic study of the micellization process was made for systems
where sodium dodecyl sulfate is present, allowing the identification of the effect of
different trivalent metal ions.
With the results presented in this dissertation we think we are contributing to a
better understanding of the factors that restrict or enhance the interaction between
metal ions and anionic surfactants
Assessment of the effects of the expansion of the city of Estarreja on the rational land use
The management of urban environment, together with the preservation of the natural environment and the creation of a sustainable built environment, is a complex challenge for contemporary societies. In the name of progress, cities are contributing for the degradation of all surrounding ecosystems. Therefore there is an arising demand for developing new strategies and a new urban development paradigm settled in the search for the equilibrium between natural and built environments and efficient use of resources. The objective of this paper is to analyse how the urban expansion of the city of Estarreja took place in relation to the land use, based on the land capability classification maps of the area. Based in the results some sustainable development strategies that might be applied to the city are discussed. The obtained results demonstrate that the city has been growing faster then its population, consuming vast portions of land, since its growth as been occurring in a linear form. Despite this fact, results show that most of this expansion took place towards a territory of lower agricultural potential, when comparing to the location of its original settlement
Assessment of layer thickness and uniformity in railway embankments with Ground Penetrating Radar
In the aim of a national research project entitled “Interaction soil-rail track for high speed
trains”, a protocol was established between the National Railway Network and four national research institutions
to develop the knowledge concerning the methodology for the construction and quality control of the
railway embankments and railtrack layers for high speed trains. One of the objectives of this protocol is to establish
a methodology for quality control of construction layers by different available test methods. Nondestructive
testing (NDT) methods are currently very attractive due to their ability to provide information
about layer thickness and state condition without causing damage or requiring the removal of material samples.
Within the NDT available, ground penetrating radar (GPR) is a very fast and reliable technique, whose
advantage is the repeatability and the capability of acquiring continuous data.
To reach the proposed goal, a trial embankment was constructed with different materials, layer’s thicknesses,
water contents and compaction energy levels. GPR was used in two embankments, in order to detect the
thickness of the sub-ballast layer located over the compacted sand layer and its uniformity along the track, but
also along the cross-section of the track. In order to control some parameters of the sub-ballast layer, like
thickness and uniformity, several metallic plates had been used in the base of the sub-ballast layer, along an
alignment. It shows clearly the ability of GPR to detect the sub-ballast layer and its thickness variations along
the profile
Comparative analysis of impacted upper canines : panoramic radiograph vs cone beam computed tomography
Background: The use of CBCT exam in the study of IMC is not new. However, it?s still not known in what specific aspects CBCT exam shows a better result than then conventional exams. The aim of this study was to compare and conclude in what way the opinion regarding upper canine impaction differed when observing a panoramic image compared to the observation of a set of CBCT reconstructions. Materials and Methods: Twenty patients (10 males and 10 females) with a total of 28 impacted maxillary canines were identified from the database of the Department of Dentistry, Faculty of Medicine, University of Coimbra. For each canine, two different images were available: a panoramic image and a set of CBCT reconstructions. After a random distribution of both groups images, nine orthodontists completed a questionnaire where they were asked to evaluate ten different questions regarding canine impaction. Statistic analysis was performed using Cronbach?s alpha statistics, Kappa statistics and McNemar test, considering p<0,05 statistically significant. Results: This study showed differences between the two images regarding tooth position. A statistical significant poor agreement was found between the two methods for the mesio-distal position of the apex (k=0,388, p<0,001) and for the labio-palatal tip cusp position (k=0,035, p=0,114). The adjacent root resorption showed a poor and very poor agreement between the two methods. Every other items were scored with an agreement between modalities ranging from moderate to strong. Conclusions: The analyses of panoramic images versus CBCT images reconstructions provided different information regarding tooth position (especially concerning the mesio-distal apex position and the labio-palatal cusp position) but also in the assessment of root resorption. Further investigation should be done to determine in what cases CBCT exam has a clear advantage over conventional 2D exams, justifying its us
Prejudice, Vulnerability, Adhesion Process, Religiousness Regarding the Life Routine with AIDS: Life Stories
Objective: To communicate life stories of people who suffer from
acquired immunodeficiency-syndrome with a higher vulnerability
registered at the Municipal Secretary of Social Assistance and the
diagnostic’s influence on their daily routine.
Method: Descriptive and exploratory study based on oral life history.
Thirteen people with AIDs took part in the study via a semi-structured
interview. The narratives were analyzed using Bardin’s thematic content
analysis.
Results: Three thematic axes emerged from Bardin’s content analysis:
prejudice and discrimination regarding the life routine with aids; Reaction
when facing the diagnostic and the adhesion process for the
antiretroviral treatment; Confrontation of religion and religiousness on
people with aids.
Conclusion: The people living with aids, a chronic and stigmatizing
disease, need the support of multidisciplinary teams and an improvement
in relation to the access, the coverage and the meaning assigned
to the disease, besides a better quality of life and social assistance.
We conclude that religion did not contribute to facing these people’s
conditions. It brought blame, incorrect information that may impair
the treatment and their follow-up. One infers that health education regarding
HIV/AIDS needs to be remodeled on all of society’s segments
Convênio entre MDS e prefeitura municipal: prestação de contas
O estudo de caso trata da prestação de contas, por uma prefeitura municipal, da aplicação de recursos provenientes de um convênio com o Ministério de Desenvolvimento Social e Combate à Fome (MDS). A prestação de contas foi aprovada e o texto apresenta a relação das atividades e gastos efetuados e observações feitas durante a avaliação realizada pelo MDS. Este é um caso fictício usado em um curso de gestão de convênios e de contratos de repasse de recursosNúmero de páginas: 2 p.NegociaçãoGestão Orçamentária. Finanças Pública
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