New natural hydraulic lime mortars – Physical and microstructural properties in different curing conditions

Construction and Building Materials 54 (2014) 378–384

Electron Transfer and Ligand Binding Properties of Cytochromes

Dissertation presented to obtain the Ph.D degree in Biochemistry

On the physical-chemical properties of ceramide C16

Dissertation presented to obtain the Ph.D degree in Chemistry.

Synchronization properties of multi-oscillator circadian systems

Dissertation presented to obtain the Ph.D degree in Computational Biology

Technology transition towards electric mobility - technology assessment as a tool for policy design

Paper presented at the Colloquium Gerpisa 2013, Paris (http://gerpisa.org/node/2085), Session n°: 19 New kinds of mobility: old and new business models

Influence of the molecular weight in mechanical properties and degradation kinetics of chitosan inverted colloidal crystals

Tissue engineering arises from the need to regenerate organs and tissues, requiring the development of scaffolds, which can provide an optimum environment for tissue growth. In this work, chitosan with different molecular weights was used to develop biodegradable 3D inverted colloidal crystals (ICC) structures for bone regeneration, exhibiting uniform pore size and interconnected network. Moreover, in vitro tests were conducted by studying the influence of the molecular weight in the degradation kinetics and mechanical properties. The production of ICC included four major stages: fabrication of microspheres; assembly into a cohesive structure, polymeric solution infiltration and microsphere removal. Chitosan’s degree of deacetylation was determined by infrared spectroscopy and molecular weight was obtained via capillary viscometry. In order to understand the effect of the molecular weight in ICC structures, the mass loss and mechanical properties were analyzed after degradation with lysozyme. Structure morphology observation before and after degradation was performed by scanning electron microscopy. Cellular adhesion and proliferation tests were carried out to evaluate ICC in vitro response. Overall, medium molecular weight ICC revealed the best balance in terms of mechanical properties, degradation rate, morphology and biological behaviour.

Monitorização de consumos energéticos em edifícios: um estudo de caso na Schneider Electric

Na sequência do panorama económico atual, existe cada vez mais uma tendência de redução de custos e de, em simultâneo, obter a eficiência energética desejada, mais concretamente no setor dos edifícios, uma vez que este tem um peso bastante considerável nos consumos totais em Portugal e na Europa. Existem variadas formas de atuar neste sentido nomeadamente ao nível dos equipamentos e sistemas instalados, bem como, nos hábitos e comportamentos dos ocupantes. Com esse intuito, muitas empresas têm desenvolvido mecanismos ou formas de minimizar os gastos, nomeadamente em termos de consumos elétricos. Dentro dos possíveis caminhos para se alcançar esse objetivo, surgem os sistemas de monitorização e os sistemas de gestão técnica centralizada. O objetivo de reduzir a discrepância entre a fatura que se paga pela eletricidade e o que realmente consiste numa necessidade de consumo é atualmente uma preocupação real. Desta forma, o desenvolvimento de soluções com capacidade para garantir a redução do erro na tomada de decisão bem como as que tornem possível o acompanhamento do desempenho de toda a instalação em detalhe e em tempo real são áreas nas quais se tem e se vai continuar a investir. É por isso, realmente importante, perceber onde e porquê se consome mais e é um desafio alterar esse panorama e continuar a realizar a monitorização dos registos. Para tal, a empresa Schneider Electric tem instaladas estações de medida, mais concretamente analisadores de energia, nos seus quadros elétricos, de forma a conseguir percecionar os consumos de forma mais detalhada e direcionada, ou seja, permitindo visualizar dados de todas as frações do piso. 281 Esta dissertação tem como objetivo a avaliação dos consumos de eletricidade de forma detalhada, tendo como objeto de estudo o edifício onde está sediada a empresa Schneider Eletric, de forma detalhada e a posterior identificação de hábitos ou fatores que influenciem os mesmos da forma não pretendida. Tem ainda o objetivo de avaliar o comportamento da técnica solar passiva utilizada no referido edifício. Desta forma será possível saber, não só o perfil de consumos e respetivos impactos bem como sugerir possíveis ajustes que levem a uma maior eficiência energética. Os resultados deste estudo deverão permitir às pessoas responsáveis pela entidade tomar decisões assentes em informação concreta e detalhada.

Numerical prediction of diffusion and electric field-induced iron nanoparticle transport

Zero valent iron nanoparticles (nZVI) are considered very promising for the remediation of contaminated soils and groundwaters. However, an important issue related to their limited mobility remains unsolved. Direct current can be used to enhance the nanoparticles transport, based on the same principles of electrokinetic remediation. In this work, a generalized physicochemical model was developed and solved numerically to describe the nZVI transport through porous media under electric field, and with different electrolytes (with different ionic strengths). The model consists of the Nernst–Planck coupled system of equations, which accounts for the mass balance of ionic species in a fluid medium, when both the diffusion and electromigration of the ions are considered. The diffusion and electrophoretic transport of the negatively charged nZVI particles were also considered in the system. The contribution of electroosmotic flow to the overall mass transport was included in the model for all cases. The nZVI effective mobility values in the porous medium are very low (10−7–10−4 cm2 V−1 s−1), due to the counterbalance between the positive electroosmotic flow and the electrophoretic transport of the negatively charged nanoparticles. The higher the nZVI concentration is in the matrix, the higher the aggregation; therefore, low concentration of nZVI suspensions must be used for successful field application.

Psychometric properties of the Psychopathy Checklist : Youth version among portuguese juvenile delinquents

The main aim of the present study was to examine some psychometric properties of the Psychopathy Checklist: Youth Version (PCL:YV) among Portuguese juvenile delinquents. With forensic sample of 192 incarcerated male participants, the Portuguese version of the PCL:YV demonstrated promising psychometric properties of the three-factor model of youth psychopathy, internal consistency, convergent validity, concurrent validity, and retrospective validity that generally justify its use among Portuguese youths. Statistically significant associations were found with age of criminal onset, frequency of crimes, number of victims, and use of physical violence.

Field-effect transistors based on Zinc oxide nanoparticles

This work reports the development of field-effect transistors (FETs), whose channel is based on zinc oxide (ZnO) nanoparticles (NPs). Using screen-printing as the primary deposition technique, different inks were developed, where the semiconducting ink is based on a ZnO NPs dispersion in ethyl cellulose (EC). These inks were used to print electrolyte-gated transistors (EGTs) in a staggered-top gate structure on glass substrates, using a lithium-based polymeric electrolyte. In another approach, FETs with a staggered-bottom gate structure on paper were developed using a sol-gel method to functionalize the paper’s surface with ZnO NPs, using zinc acetate dihydrate (ZnC4H6O4·2H2O) and sodium hydroxide (NaOH) as precursors. In this case, the paper itself was used as dielectric. The various layers of the two devices were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric and differential scanning calorimetric analyses (TG-DSC). Electrochemical impedance spectroscopy (EIS) was used in order to evaluate the electric double-layer (EDL) formation, in the case of the EGTs. The ZnO NPs EGTs present electrical modulation for annealing temperatures equal or superior to 300 ºC and in terms of electrical properties they showed On/Off ratios in the order of 103, saturation mobilities (μSat) of 1.49x10-1 cm2(Vs)-1 and transconductance (gm) of 10-5 S. On the other hand, the ZnO NPs FETs on paper exhibited On/Off ratios in the order of 102, μSat of 4.83x10- 3 cm2(Vs)-1and gm around 10-8 S.

Magnetotransport properties of metal/LaAlO3/SrTiO3 heterostructures

The quasi two-dimensional electron gas (q2DEG) hosted in the interface of an epitaxially grown lanthanum aluminate (LaAlO3) thin film with a TiO2-termi-nated strontium titanate (SrTiO3) substrate (001) has been massively studied in the last few years. The confinement of mobile electrons to within a few nanome-ters from the interface, superconductive behavior at low temperatures and elec-tron mobility exceeding 1000 cm2/(V.s) make this system an interesting candi-date to explore the physics of spin injection and transport. However, due to the critical thickness for conduction of 4 unit cells (uc) of LaAlO3, a high tunneling resistance hampers electrical access to the q2DEG, preventing proper injection of spin polarized current. Recently, our group found that depositing a thin overlayer of Co on LaAlO3 reduces the critical thickness, enabling conduction with only 1 uc of LaAlO3. Two scenarios arise to explain this phenomenon: a pinning of the Fermi level in the metal, inducing charge transfer in the SrTiO3; the creation of oxygen vacancies at the interface between LaAlO3 and the metal, leading to an n-type doping of the SrTiO3. In this dissertation, we will report on magnetotransport of metal/LaAlO3/SrTiO3 (metal: Ti, Ta, Co, Py, Au, Pt, Pd) heterostructures with 2 uc of LaAlO3 studied at low temperatures (2 K) and high magnetic fields (9 T). We have analyzed the transport properties of the gas, namely, the carrier concen-tration, mobility and magnetotransport regime and we will discuss the results in the light of the two scenarios mentioned above.

Historic and potential technology transition paths of grid battery storage: Co-evolution of energy grid, electric mobility and batteries

Scarcity of fuels, changes in environmental policy and in society increased the interest in generating electric energy from renewable energy sources (RES) for a sustainable energy supply in the future. The main problem of RES as solar and wind energy, which represent a main pillar of this transition, is that they cannot supply constant power output. This results inter alia in an increased demand of backup technologies as batteries to assure electricity system safety. The diffusion of energy storage technologies is highly dependent on the energy system and transport transition pathways which might lead to a replacement or reconfiguration of embedded socio-technical practices and regimes (by creating new standards or dominant designs, changing regulations, infrastructure and user patterns). The success of this technology is dependent on hardly predictable future technical advances, actor preferences, development of competing technologies and designs, diverging interests of actors, future cost efficiencies, environmental performance, the evolution of market demand and design and evolution of our society.

Temperature influence and social interaction on the frequency of electric organ discharges in Rhamphicthys rostratus.

The frequency of electric organ discharges (EOD) of a gymnotiform fish of "pulse" frequency (40-100 Hz) from South America - Ramphicthys rostratuswas studied. The animals were settled in pairs in a aquarium and thus observed: variation in EOD frequency had at least two components: one more positively correlated with temperature, another less positively correlated due to social interaction.

Soil physical and Chemical properties of cultivated pasture on forest land, Roraima, Brazil .

Soil conditions under pasture were examined in a range of sites representing the sequence of conversion of forest to pasture at two locations in the vicinity of Ilha de Maracã, Roraima. Comparisons were made with adjacent savana. Soil bulk densities shown to increase after forest clearance and soil chemical data indicate that the initial beneficial effects on nutrient supply of burning forest debris are rather short-lived. Very low levels of available phosphorus prevail in areas of savanna and cultivated pasture of all ages. Variations in the status of older cultivated pastures are mainly attributable to different grazing levelt.