Alexandre Borges

Qualidade da corvina (Micropogonias furnieri) eviscerada em diferentes períodos de estocagem a 0°C

This study was aimed at determining the shelf-life of gutted croaker (Micropogonias furnieri) and stocked at 0°C using physical-chemical and sensory analyses. On the 14th day of storage, the pH of the muscle tissue reached the accepted limit for consumption (6.4). The levels of TVB were kept within the stipulated values for consumption (30mgN 100g-1) until the 21st day. In 28 days of storage at 0°C, the histamine level did not excess the acceptable level of 10mg 100g-1 of meat. The quantitative descriptive analysis method employed 9 attributes to describe the croaker. The study found that aroma and taste of sea fish, aroma and taste of marshy smell, bitterness, and the color of the meet were the most important aspects differentiating samples after 0, 4, 7, 10, 14 days of stocking at 0°C. According to the obtained results, and based on the standards of national and international legislation, it was confirmed that the commercial shelf-life of gutted croaker (Micropogonias furnieri) stored at 0°C is 14 days.

Preionization effects of iso-C4H10 in N2 TE UV lasers

In this paper the ionizing role of isobutane (iso-C4H10) in the operation of a N2TE UV laser is analyzed. Laser pulse width value modifications, different laser wavelengths generated in the 2+ system and voltage pulse period modifications are analysed in order to show that isobutane, in very reduced quantities, generates a preionizing effect that can be higher than that produced by a conventional wire preionization system.

Additives as ionizing elements in N2 TE UV lasers

This work reports the role some additives have in pre-ionizing a N2 TE UV laser (337.1 nm). The modifications in both stimulated radiation characteristics and excitation-pulse period prove the different ionizing power of each element. The laser operating without a pre-ionizing wire device and with N2 plus different additives was able to generate pulses with a temporal width of the same order than those obtained when it was operating with N2 and a pre-ionizing wire device. Also, a relation between ionization efficiency and interelectrode distance has been established allowing the prediction of conditions for optimum laser-pulse width generation.