State-of-the-art of spatial arch bridges

The paper describes a new form of bridge called a spatial arch bridge. This bridge type was developed in response to the demand for landmark structures, which have started to appear in the modern urban landscape to provide a symbol of originality, innovation and progress. Spatial arch bridges are defined as bridges in which the vertical deck loads produce bending moments and shear forces not contained in the arch plane, owing to their geometrical and structural configuration. Moreover, the arch itself may not be contained in a plane. The different variables and geometries that create such a structural configuration have been studied and classified. A wide compilation of examples of this bridge type has been made in chronological order, according to their construction date, from Maillarts first concrete spatial arch bridges to the latest designs and materials

Efeito do tipo de descasque e da temperatura de armazenamento na qualidade de laranjas 'Pera' minimamente processadas Effect of type of peeling and storage temperature on quality of minimally processed "Pera-rio" oranges

O objetivo deste trabalho foi avaliar a influência do tipo de descasque, manual, mecânico e enzimático, e do armazenamento, a 5ºC e 10ºC e ambiente (21-23ºC), na vida útil de laranjas 'Pêra' do tipo Rio, minimamente processadas. As laranjas foram colhidas maduras, e imediatamente lavadas, higienizadas e descascadas. Após a eliminação da casca, as frutas foram desinfetadas e embaladas em bandejas de isopor revestidas com filme PVC esticável. Durante o armazenamento sob as diferentes temperaturas, avaliaram-se a aparência, a quantidade de suco drenado, o aparecimento de podridões, a perda de massa fresca, a intensidade respiratória, os conteúdos de O2 e CO2 no interior das embalagens, a coloração, os teores de ácido ascórbico (AA) e de sólidos solúveis totais (SST), e acidez titulável (AT), assim como a relação SST/AT. Foram realizadas avaliações microbiológicas, bem como testes de aceitabilidade e de preferência de compra pelo consumidor. Somente os produtos descascados enzimaticamente (DE) apresentaram perda de suco, que aumentou com o tempo e a temperatura de armazenamento. A perda de massa fresca ocorreu em todos os produtos, mas os DE e os armazenados a 21-23ºC apresentaram os maiores valores. Todas as laranjas processadas apresentaram pico respiratório na primeira hora após o descascamento, seguido de redução e estabilização. O descascamento enzimático e as menores temperaturas de armazenamento levaram aos teores mais elevados de O2 e aos mais baixos de CO2, nas embalagens. As frutas processadas apresentarem baixa contagem de microrganismos mesófilos, psicrófilos e coliformes totais, e ausência de coliformes fecais. Podridões apareceram nas descascadas manual (DM) e mecanicamente (DME) após 13 dias, 8 dias e 4 dias a 5ºC e 10ºC e ambiente (21-23ºC), respectivamente. Os produtos obtidos com descascamento manual (DM) não diferiram dos DME ou DE, quanto aos teores de AT, SST e AA e relação SST/AT. Os produtos DM e DME, armazenados a 5ºC, foram os preferidos pelos provadores e apresentaram boa aparência por 19 dias e bom sabor por 23 dias. Os DE e armazenados a 5ºC apresentaram boa aparência por 4 dias e sabor desagradável no 1º dia.<br>The aim of this work was to evaluate the influence of type of peeling, manual, mechanic and enzymatic, and temperature of storage, 5ºC, 10ºC and ambient (21-23ºC) on the shelf-life of minimally processed 'Pera' type Rio oranges. Ripe oranges were picked and immediately washed and peeled. After peeled, fruits were disinfected and packed on polystyrene trays recovered with stretchable PVC film. During storage, was evaluated the appearance, amount of juice loss, rotting, loss of fresh mass, respiratory intensity, level of O2 and CO2 inside the packages, color, contents of total soluble solids (TSS), titratable acidity (TA) and ascorbic acid (AA) and the ratio TSS/TA. Microbiological evaluations were made as well as testing acceptance and preference by the consumer. Only enzymatically peeled products presented juice loss that increased with storage time. There was continuous loss of fresh mass in every product, but peeled products stored at 21-23ºC presented the greatest losses. Processed oranges presented a respiratory peak at the first hour after peeling followed by reduction and stabilization at 11th-13th hour. The enzymatic peeling and the lowest storage temperatures produces the highest contents of O2 and the lowest of CO2 in packages. Processed fruits presented low counting of microorganisms, mesophilic, psychrotrophs and coliforms. Fecal coliforms were not detected. Rotting appeared on manually and mechanically peeled after 13 days at 5ºC, 8 days at 10ºC or 4 days at 21-23ºC. Products obtained from manual peeling did not differ from mechanically or enzymatically peeled related to contents of TA, TSS and AA and the ratio (TSS/TA). Products manually or mechanically peeled, and stored at 5ºC , were considered the best by the tasters and presented good appearance during 19 days and good taste for 23 days. Products enzymatically peeled and stored at 5ºC presented good appearance for four days and unpleasant taste in the first day