Obtenção de Suco Misto de Açaí, Morango e Acerola por diferentes processos de secagem.

A preocupação da população em consumir alimentos mais saudáveis tem proporcionado um aumento do consumo de sucos de frutas sendo que o desenvolvimento de sucos mistos tem se caracterizado como uma nova tendência. A comercialização do suco na forma de pó apresenta vantagens quanto a estabilidade química e microbiológica. O presente estudo teve como objetivo desenvolver um suco misto em pó de açaí, morango e acerola utilizando dois processos de secagem: liofilização e secagem com ar quente. Seguindo o delineamento de mistura centroide simplex, preparou-se um suco misto com 10 formulações diferentes, com polpa de açaí variando entre 10 e 80%, morango entre 10 e 80% e acerola entre 10 e 80%. A soma das 3 variáveis foi mantida igual a 100%. As 10 formulações foram avaliadas quanto ao teor de vitamina C, sólidos totais e aceitação sensorial (cor, sabor, consistência e impressão global). A formulação selecionada foi aquela com boa aceitação sensorial e elevado teor de ácido ascórbico. Em seguida, testou-se 2 tipos de emulsificantes (Albumina e Emustab®) em 4 níveis (2.5, 5, 7.5 e 10%) para elaboração de uma espuma a partir da mistura de polpas na proporção previamente selecionada. As espumas foram avaliadas quanto a densidade e estabilidade. A espuma elaborada foi seca em 7 temperaturas (40, 45, 50, 55, 60, 65 e 70 ºC) e selecionou-se aquela que proporcionou menor perda de vitamina C. A mistura de polpas, bem como a espuma foram desidratadas em secador convencional e liofilizador e os produtos secos obtidos foram avaliados quanto a solubilidade e umidade de equilíbrio. Os sucos reconstituídos a partir dos pós provenientes dos diferentes processos foram comparados com o suco in natura quanto as seguintes características: coordenadas de cor (L*, a*, b*, C*, h*), acidez titulável, pH, sólidos solúveis e porcentagem de vitamina C. A formulação contendo 33,33% de cada polpa de fruta foi considerada a melhor. A espuma elaborada com 5% de albumina foi utilizada para as subsequentes secagens devido a sua baixa densidade e boa estabilidade. A temperatura de 60 ºC foi a que ocasionou menores perdas de vitamina C durante secagem em leito de espuma. Os pós obtidos pelos 2 processos apresentaram solubilidade média de 46,5%, considerada baixa. A umidade final foi menor para a espuma liofilizada (3,25%). O processo de liofilização foi mais eficiente na preservação da vitamina C do que o processo utilizando ar quente independente da adição de emulsificante. As coordenadas de cor, acidez titulável, sólidos solúveis e pH sofreram pequenas variações em função do tipo de processo. A adição de emulsificante aumentou o pH e o teor de sólidos solúveis. Em geral, pode-se concluir que é possível elaborar um suco misto em pó utilizando liofilização ou secagem com ar quente

Space station architectural elements model study

The worksphere, a user controlled computer workstation enclosure, was expanded in scope to an engineering workstation suitable for use on the Space Station as a crewmember desk in orbit. The concept was also explored as a module control station capable of enclosing enough equipment to control the station from each module. The concept has commercial potential for the Space Station and surface workstation applications. The central triangular beam interior configuration was expanded and refined to seven different beam configurations. These included triangular on center, triangular off center, square, hexagonal small, hexagonal medium, hexagonal large and the H beam. Each was explored with some considerations as to the utilities and a suggested evaluation factor methodology was presented. Scale models of each concept were made. The models were helpful in researching the seven beam configurations and determining the negative residual (unused) volume of each configuration. A flexible hardware evaluation factor concept is proposed which could be helpful in evaluating interior space volumes from a human factors point of view. A magnetic version with all the graphics is available from the author or the technical monitor

Control of uncertain compartmental systems

\ A study of the performance of mass control for compartmental systems, under the presence of uncertainties, is presented. Bounds for the asymptotical mass offset are derived as a functional of the uncertainty bounds. The obtained results are illustrated by simulations for the case of neuromuscular blockade control of patients undergoing surgery

Mechanically-Induced Transport Switching Effect in Graphene-based Nanojunctions

We report a theoretical study suggesting a novel type of electronic switching effect, driven by the geometrical reconstruction of nanoscale graphene-based junctions. We considered junction struc- tures which have alternative metastable configurations transformed by rotations of local carbon dimers. The use of external mechanical strain allows a control of the energy barrier heights of the potential profiles and also changes the reaction character from endothermic to exothermic or vice-versa. The reshaping of the atomic details of the junction encode binary electronic ON or OFF states, with ON/OFF transmission ratio that can reach up to 10^4-10^5. Our results suggest the possibility to design modern logical switching devices or mechanophore sensors, monitored by mechanical strain and structural rearrangements.Comment: 10 pages, 4 figure

Non-collinear coupling between magnetic adatoms in carbon nanotubes

The long range character of the exchange coupling between localized magnetic moments indirectly mediated by the conduction electrons of metallic hosts often plays a significant role in determining the magnetic order of low-dimensional structures. In addition to this indirect coupling, here we show that the direct exchange interaction that arises when the moments are not too far apart may induce a non-collinear magnetic order that cannot be characterized by a Heisenberg-like interaction between the magnetic moments. We argue that this effect can be manipulated to control the magnetization alignment of magnetic dimers adsorbed to the walls of carbon nanotubes.Comment: 13 pages, 5 figures, submitted to PR

Bromeliaceae species from coastal restinga habitats, Brazilian states of Rio de Janeiro, Espírito Santo, and Bahia.

Bromeliaceae is one of the most representative plant families in restinga habitats. We analyzed the speciesrichness and composition of Bromeliaceae in 13 restinga habitats along the Brazilian coast. We found a total of 41species distributed along the restinga habitats studied. The restinga of Praia do Sul, in the state of Rio de Janeiro, hadthe highest number of species (15), whereas the restinga of Abaeté, in the state of Bahia, had the lowest (4). Our dataare suggestive that the Doce River may represent the limit of distribution for some bromeliad species, with some speciesoccurring only south of that river and others occurring only to the north of it. The differences in Bromeliaceae speciescomposition among restinga habitats probably are not only due to differences in local environmental conditions, butalso due to the geographic distribution pattern of each species and to the present degree of disturbance at each restinga