Pràctica 9: Les tecnologies de la informació i la comunicació (TIC) en l'entorn escolar

Les conseqüències educatives del desenvolupament de les tecnologies de la informació i la comunicació (TIC) i de la utilització d’aquestes als centres escolars és objecte d’un intens debat per la influència que tenen en el desenvolupament infantil. En l’etapa de 3 a 6 anys, els aspectes emocionals i de relació amb els iguals són fonamentals per a l’evolució dels xiquets i xiquetes; per aquest motiu l’ús de les TIC ha de fer-nos reflexionar sobre les interaccions socials que es generen o s’esbiaixen, a més d’analitzar la capacitat d’utilització d’aquestes, de forma creativa i responsable. En l’entorn escolar, les TIC es poden usar simplement per a transmetre informació totalment elaborada i fomentar una resposta passiva o repetitiva de part de l’alumnat o, per contra, la utilització de les TIC pot convertir-se en un instrument significatiu en el procés d’aprenentatge infantil. La presència i el impacte de les TIC és una realitat en la vida social i per aquest motiu també les trobem en l’àmbit educatiu. Una anàlisi rigorosa del seu ús serà fonamental per a fomentar un desenvolupament social i cognitiu adequat en els xiquets i xiquetes.

Avaliação de perdas invisíveis na colheita mecanizada em dois fluxos de massa de cana-de-açúcar

In this work the performance of a sugar cane chopped harvester was analysed when fed with two sugar cane mass flows, measuring the invisible losses, which are impossible to measure in the field, harvester sugar cane cleaning efficiency and air velocity on extractors exit. The trial was done under controlled conditions at Copersucar Technology Center in January 2000. The results showed that the flow of sugar cane through the harvester doesn't influence the magnitudes of total invisible losses and raw material cleaning efficiency. The mean air velocity on the primary extractors exit was 12.0 m s-1, and 9.2 m s-1 on the secondary extractor, with a coefficient of variation of 21%, indicating that the poor cleaning performance of the harvester could be related to air velocity difference inside the extractor. Analyzing the data collected in the trials, it was possible to conclude that invisible losses in sugar cane harvester were 10% and the cleaning efficiency was 87%.

Transferência de massa e secagem em leitos vibrofluidizados: uma revisão

Development of processing technology and equipments requires new methods and better quality of the processed product. In the continuous drying process, utilization of equipments that promotes an increment in the transfer coefficients becomes of the major interest. The use of vibrational energy has been recommended to the dispersed materials. Such method is based on the use of vibrational energy applied to disperse media. Thus, a literature review on the mass transfer and drying in vibro-fluidized beds was carried out, showing experimental results and mathematical modeling.

COMPARAÇÃO DAS PROPRIEDADES REOLÓGICAS DA MASSA DE CACAU TORRADA CONVENCIONALMENTE E POR MICROONDAS

Two kinds of roasting cocoa system: conventional batch method in electrical oven, and by microwaves, in a continuous microwave rotary applicator (2450MHz), were compared with respect to viscosity. Cocoa was roasted in whole beans and in nibs. The variable used in the microwave treatment was the power density applied to the whole beans (254,45 to 290,80 Wh/kg) and to the nibs (227,27 to 262,23 Wh/kg), with a constant holding time of 10 minutes. The variable used in the conventional roasting process was the roasting time of the beans (40 to 44 min) and the nibs (34 to 38 min), with constant temperature in the jacket of electric oven (150°C). Viscosity was measured in a Brookfield rheometer (mod RV-DVIII) at 40°C. In general, the plastic viscosity of the microwaved samples was lower than that of the conventional roasted samples. Also the nibs showed lower viscosities than the whole beans when roasted in the electric oven. The viscosity of the samples roasted in the microwave oven was lower in the whole beans than in the nibs. The product was sensorially evaluated by three experts in cocoa flavour, and it was shown that the flavour of the microwave roasted products was similar to that of the conventionally roasted products, with the advantage of a reduction in process time.