Monitorização e caracterização de uma UTA com tecnologia exsicante-evaporativa assistida por energia solar de acordo com a metodologia definida no âmbito da AIE SHC task 38

A presente dissertação fundamenta-se na monitorização e análise de uma “Unidade de Tratamento de Ar” baseada em tecnologia exsicante evaporativa assistida por energia solar. Primeiramente é apresentado um conjunto de conceitos associados ao tema abordado, de modo a facilitar a compreensão dos fenómenos termodinâmicos envolvidos. Após a abordagem inicial que serve de consolidação, é feito o ponto da situação actual, quer em termos tecnológicos, quer em termos de instalações existentes. A etapa seguinte da dissertação descreve pormenorizadamente a instalação do LNEG e seus princípios de funcionamento, nesta fase também é contemplada a descrição sumária dos equipamentos, dos componentes e dos elementos de medição e controlo presentes no sistema. A metodologia seguida assenta fortemente em dois pontos; primeiro, a monitorização do sistema através do software “Agilent VEE Pro” e pela análise dos dados recolhidos com auxílio da folha de cálculo do LNEG, desenvolvida especialmente para este sistema. Em segundo lugar, a metodologia seguida será a imposta pela “Tarefa 38” de acordo com a Agência Internacional de Energia, no âmbito do programa de Aquecimento e Arrefecimento Solar o que permite a comparação de sistemas a nível internacional. Alias a “Tarefa 38” pretende desenvolver esta tecnologia, ao nível da concepção, estandardização, optimização das instalações, conceder o fácil acesso à informação e promover a comparabilidade de resultados. O desempenho global do sistema é bastante positivo, o bom comportamento do sistema é ilustrado na análise gráfica feita nos modos de aquecimento e arrefecimento. O grau de satisfação dos utilizadores é bom e o sistema demonstra capacidade para manter o conforto térmico dos espaços a climatizar de acordo com as normas e regulamentos em vigor. A utilização das energias renováveis nos dias de hoje, como por exemplo a energia solar é mais do que uma obrigação, é um dever.

New Technique for Uniform Voltage Sharing in Series Stacked Semiconductors

This paper describes the operation of a solid-state series stacked topology used as a serial and parallel switch in pulsed power applications. The proposed circuit, developed from the Marx generator concept, balances the voltage stress on each series stacked semiconductor, distributing the total voltage evenly. Experimental results from a 10 kV laboratory series stacked switch, using 1200 V semiconductors in a ten stages solid-state series stacked circuit, are reported and discussed, considering resistive, capacitive and inductive type loads for high and low duty factor voltage pulse operation.

Exposure to dust in poultry: the importance of task differences for detailed exposure assessment

Dust is a complex mixture of particles of organic and inorganic origin and different gases absorbed in aerosol droplets. In a poultry unit include dried faecal matter and urine, skin flakes, ammonia, carbon dioxide, pollens, feed and litter particles, feathers, grain mites, fungi spores, bacteria, viruses and their constituents. Dust particles vary in size and differentiation between particle size fractions is important in health studies in order to quantify penetration within the respiratory system. A descriptive study was developed in order to assess exposure to particles in a poultry unit during different operations, namely routine examination and floor turn over. Direct-reading equipment was used (Lighthouse, model 3016 IAQ). Particle measurement was performed in 5 different sizes (PM0.5; PM1.0; PM2.5; PM5.0; PM10). The chemical composition of poultry litter was also determined by neutron activation analysis. Normally, the litter of poultry pavilions is turned over weekly and it was during this operation that the higher exposure of particles was observed. In all the tasks considered PM5.0 and PM10.0 were the sizes with higher concentrations values. PM10 is what turns out to have higher values and PM0.5 the lowest values. The chemical element with the highest concentration was Mg (5.7E6 mg.kg-1), followed by K (1.5E4 mg.kg-1), Ca (4.8E3 mg.kg-1), Na (1.7E3 mg.kg-1), Fe (2.1E2 mg.kg-1) and Zn (4.2E1 mg.kg-1). This high presence of particles in the respirable range (<5–7μm) means that poultry dust particles can penetrate into the gas exchange region of the lung. Larger particles (PM10) present a range of concentrations from 5.3E5 and 3.0E6 mg/m3.

Children's metalinguistic activity in the construction of linguistic existence

In this paper we examine the construction of first entities in narratives produced by children of 5, 7, 10 years and adults1 . The study demonstrates that when children reformulate they try to construct entities detached from the situation of enunciation, which means that they construct a detached or a translated plane and they construct linguistic existence of entities. Entities must first be introduced into the enunciative space and then comments will be made in subsequent utterances. Constructing existence supposes extraction. This consists of “singling out an occurrence, that is, isolating and drawing its spatiotemporal boundaries” (Culioli, 1990, p. 182) . Once the occurrence of the notion is constructed (which means it has become a separate occurrence with situational properties), children can predicate about it. However, there are children who do not construct the linguistic existence of entities. I hypothesize that the mode of task presentation influences the success of constructing linguistic existence. Sharing the investigator’s knowledge about the stimulus images, children do not ascribe an existential status to the occurrence of the notional domain.

Sequencing of a 9.9 kb segment on the right arm of yeast chromosome VII reveals four open reading frames, including PFK1, the gene coding for succinyl-CoA synthetase (beta-chain) and two ORFs sharing homology with ORFs of the yeast chromosome VIII

A 9.9 kb DNA fragment from the right arm of chromosome VII of Saccharomyces cerevisiae has been sequenced and analysed. The sequence contains four open reading frames (ORFs) longer than 100 amino acids. One gene, PFK1, has already been cloned and sequenced and the other one is the probable yeast gene coding for the beta-subunit of the succinyl-CoA synthetase. The two remaining ORFs share homology with the deduced amino acid sequence (and their physical arrangement is similar to that) of the YHR161c and YHR162w ORFs from chromosome VIII.

Task-based occupational exposure assessment and particle number concentration: two important data resources to perform risk assessment for occupational exposure to particles

Environment monitoring has an important role in occupational exposure assessment. However, due to several factors is done with insufficient frequency and normally don´t give the necessary information to choose the most adequate safety measures to avoid or control exposure. Identifying all the tasks developed in each workplace and conducting a task-based exposure assessment help to refine the exposure characterization and reduce assessment errors. A task-based assessment can provide also a better evaluation of exposure variability, instead of assessing personal exposures using continuous 8-hour time weighted average measurements. Health effects related with exposure to particles have mainly been investigated with mass-measuring instruments or gravimetric analysis. However, more recently, there are some studies that support that size distribution and particle number concentration may have advantages over particle mass concentration for assessing the health effects of airborne particles. Several exposure assessments were performed in different occupational settings (bakery, grill house, cork industry and horse stable) and were applied these two resources: task-based exposure assessment and particle number concentration by size. The results showed interesting results: task-based approach applied permitted to identify the tasks with higher exposure to the smaller particles (0.3 μm) in the different occupational settings. The data obtained allow more concrete and effective risk assessment and the identification of priorities for safety investments.

Generalização matemática baseada na análise de padrões numa turma de 3.º ano

Relatório de Estágio apresentado à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ensino do 1.º e 2.º ciclo do Ensino Básico