774 resultados para Alternate current biosusceptometry
Resumo:
Directed Research Internship
Resumo:
A Work Project, presented as part of the requirements for the Award of a Master’s Double Degree in Finance from Maastricht University and NOVA – School of Business and Economics
Resumo:
This work project intends to evaluate the effectiveness of the Portuguese Government’s strategy to promote the orderly deleveraging of the corporate sector in the context of the current economic crisis. The recommendations of the Troika and the commitments assumed under the Memorandum of Understanding signed by the Government in 2011 required the creation of formal processes to avoid disorderly deleveraging. Conclusions and recommendations were drawn based on past experiences of large-scale corporate restructuring strategies in other countries and on the analysis of financial and statistical data on companies applying for “Programa Especial de Revitalização”.
Resumo:
Introduction Chagasic megaesophagus (CM) is the most common digestive manifestation of Chagas disease in Brazil, and the State of Goiás is one of the most affected regions. In recent decades, the Hospital das Clínicas (HC)/Universidade Federal de Goiás (UFG) has been a reference center for the study and treatment of CM. The objective of this study was to characterize the current epidemiological profile of patients with CM observed at the HC of the UFG from 1998 to 2010. Methods In total, 939 patient records were analyzed, and age, gender, place of birth, serology, symptoms and radiological classification according to Rezende et al. were analyzed. Results The median patient age was 55 years. Male patients were more (54%) prevalent than female patients. The prevalence of younger patients (less than 31 years of age) was 4.2%, but 82.1% of the younger patients were from State of Bahia. Patients older than 40 years were the majority (85.5%). The radiological groups were distributed as follows: Group I (35.9%), Group II (32.9%), Group III (17%) and Group IV (14.2%). Conclusions Compared with previous studies by the same group in 1975, 1994 and 1995, the number of younger patients decreased, and the frequency curve has shifted to older patients.
Resumo:
This paper aims to provide strategies for the organic supermarket chain “Alnatura” to shape the demand and its market share of the organic food & beverage (F&B) market in Germany within the next five years. Through the historic evolution and the current market assessment of Germany, compared to a benchmark country (US), as well as prospective trends in Germany, reasons and opportunities for market growth are evaluated. In addition, an industry attractiveness, competitor and company analysis is executed. Based on those findings and a conducted survey, suggestions to adjust Alnatura´s current business strategies are deduced and finally examined on its risk and feasibility.
Resumo:
The objective of this dissertation was to explore the German men’s grooming market and to discuss the usage and purchase behavior of young male adults. After a brief market analysis, this dissertation evaluates the results of qualitative and quantitative research. The conducted research explored the consumer’s reasoning for and attitude towards personal grooming, and their attitude towards product attributes and the aging process. The dissertation concludes that men attach high value to personal grooming but only to the extent that their personal need is satisfied. As the male involvement in MG is highly dependent on each consumer’s individual needs, the market requires a careful segmentation.
Resumo:
The weak fixation of biomaterials within the bone structure is one of the major reasons of implants failures. Calcium phosphate (CaP) coatings are used in bone tissue engineering to improve implant osseointegration by enhancing cellular adhesion, proliferation and differentiation, leading to a tight and stable junction between implant and host bone. It has also been observed that materials compatible with bone tissue either have a CaP coating or develop such a calcified surface upon implantation. Thus, the development of bioactive coatings becomes essential for further improvement of integration with the surrounding tissue. However, most of current applied CaP coatings methods (e.g. physical vapor deposition), cannot be applied to complex shapes and porous implants, provide poor structural control over the coating and prevent incorporation of bioactive organic compounds (e.g. antibiotics, growth factors) because of the used harsh processing conditions. Layer-by-layer (LbL) is a versatile technology that permits the building-up of multilayered polyelectrolyte films in mild conditions based on the alternate adsorption of cationic and anionic elements that can integrate bioactive compounds. As it is recognized in natureâ s biomineralization process the presence of an organic template to induce mineral deposition, this work investigate a ion based biomimetic method where all the process is based on LbL methodology made of weak natural-origin polyelectrolytes. A nanostructured multilayer component, with 5 or 10 bilayers, was produced initially using chitosan and chondroitin sulphate polyelectrolyte biopolymers, which possess similarities with the extracellular matrix and good biocompatibility. The multilayers are then rinsed with a sequential passing of solutions containing Ca2+ and PO43- ions. The formation of CaP over the polyelectrolyte multilayers was confirmed by QCM-D, SEM and EDX. The outcomes show that 10 polyelectrolyte bilayer condition behaved as a better site for initiating the formation of CaP as the precipitation occur at earlier stages than in 5 polyelectrolyte bilayers one. This denotes that higher number of bilayers could hold the CaP crystals more efficiently. This work achieved uniform coatings that can be applied to any surface with access to the liquid media in a low-temperature method, which potentiates the manufacture of effective bioactive biomaterials with great potential in orthopedic applications.
Resumo:
This paper presents a comprehensive comparison of a current-source converter and a voltage-source converter for three-phase electric vehicle (EV) fast battery chargers. Taking into account that the current-source converter (CSC) is a natural buck-type converter, the output voltage can assume a wide range of values, which varies between zero and the maximum instantaneous value of the power grid phase-to-phase voltage. On the other hand, taking into account that the voltage-source converter (VSC) is a natural boost-type converter, the output voltage is always greater than the maximum instantaneous value of the power grid phase-to-phase voltage, and consequently, it is necessary to use a dc-dc buck-type converter for applications as EV fast battery chargers. Along the paper is described in detail the principle of operation of both the CSC and the VSC for EV fast chargers, as well as the main equations of the power theory and current control strategies. The comparison between both converters is mainly established in terms of the total harmonic distortion of the grid current and the estimated efficiency for a range of operation between 10 kW and 50 kW.
Resumo:
This paper presents a three-phase three-level fast battery charger for electric vehicles (EVs) based in a current-source converter (CSC). Compared with the traditional voltage-source converters used for fast battery chargers, the CSC can be seen as a natural buck-type converter, i.e., the output voltage can assume a wide range of values, which varies between zero and the maximum instantaneous value of the power grid phase-to-phase voltage. Moreover, using the CSC it is not necessary to use a dc-dc back-end converter in the battery side, and it is also possible to control the grid current in order to obtain a sinusoidal waveform, and in phase with the power grid voltage (unitary power factor). Along the paper is described in detail the proposed CSC for EVs fast battery charging systems: the circuit topology, the power control theory, the current control strategy and the grid synchronization algorithm. Several simulation results of the EV fast battery charger operating with a maximum power of 50 kW are presented.
Resumo:
Solar photovoltaic systems are an increasing option for electricity production, since they produce electrical energy from a clean renewable energy resource, and over the years, as a result of the research, their efficiency has been increasing. For the interface between the dc photovoltaic solar array and the ac electrical grid is necessary the use of an inverter (dc-ac converter), which should be optimized to extract the maximum power from the photovoltaic solar array. In this paper is presented a solution based on a current-source inverter (CSI) using continuous control set model predictive control (CCS-MPC). All the power circuits and respective control systems are described in detail along the paper and were tested and validated performing computer simulations. The paper shows the simulation results and are drawn several conclusions.
Resumo:
This paper presents the proposal of a three phase current source shunt active power filter (CS-SAPF) with photovoltaic grid interface. The proposed system combines the compensation of reactive power and harmonics with the injection of energy from a solar photovoltaic array into the electrical power grid. The proposed equipment presents the advantage of giving good use to the current source inverter, even when the solar photovoltaic array is not producing energy. The paper describes the control system of the CS SAPF, the energy injection control strategy, and the current harmonics and power factor compensation strategy. Simulation results to assess the performance of the proposed system are also presented.
Resumo:
FCT PhD grant SFRH/BD/80682/2011; FCT research project VisCoDyn EXPL/ECM-EST/1323/2013
Resumo:
The authors would like to thank the financial support from the NovoNordiskFoundation.
Resumo:
It has been already shown that delivering tDCS that are spaced by an interval alters its impact on motor plasticity. These effects can be explained, based on metaplasticity in which a previous modification of activity in a neuronal network can change the effects of subsequent interventions in the same network. But to date there is limited data assessing metaplasticity effects in cognitive functioning.