Technoeconomic and life-cycle analysis of single-step catalytic conversion of wet ethanol into fungible fuel blendstocks

Technoeconomic and life-cycle analyses are presented for catalytic conversion of ethanol to fungible hydrocarbon fuel blendstocks, informed by advances in catalyst and process development. Whereas prior work toward this end focused on 3-step processes featuring dehydration, oligomerization, and hydrogenation, the consolidated alcohol dehydration and oligomerization (CADO) approach described here results in 1-step conversion of wet ethanol vapor (40 wt% in water) to hydrocarbons and water over a metal-modified zeolite catalyst. A development project increased liquid hydrocarbon yields from 36% of theoretical to >80%, reduced catalyst cost by an order of magnitude, scaled up the process by 300-fold, and reduced projected costs of ethanol conversion 12-fold. Current CADO products conform most closely to gasoline blendstocks, but can be blended with jet fuel at low levels today, and could potentially be blended at higher levels in the future. Operating plus annualized capital costs for conversion of wet ethanol to fungible blendstocks are estimated at $2.00/GJ for CADO today and$1.44/GJ in the future, similar to the unit energy cost of producing anhydrous ethanol from wet ethanol ($1.46/GJ). Including the cost of ethanol from either corn or future cellulosic biomass but not production incentives, projected minimum selling prices for fungible blendstocks produced via CADO are competitive with conventional jet fuel when oil is$100 per barrel but not at $60 per barrel. However, with existing production incentives, the projected minimum blendstock selling price is competitive with oil at$60 per barrel. Life-cycle greenhouse gas emission reductions for CADO-derived hydrocarbon blendstocks closely follow those for the ethanol feedstock

PRODETUR: infra-estrutura e seus reflexos no turismo

Documento datado e numerado: junho/99, n. 6Equipe Responsável: Mary Lessa Alvim Ayres, Ilka Gonçalves Daemon, Paulo Cesar Siruffo Fernandes, Roberta Junqueira de A. Oliveir

Effector Memory Th1 CD4 T Cells Are Maintained in a Mouse Model of Chronic Malaria

Protection against malaria often decays in the absence of infection, suggesting that protective immunological memory depends on stimulation. Here we have used CD4+ T cells from a transgenic mouse carrying a T cell receptor specific for a malaria protein, Merozoite Surface Protein-1, to investigate memory in a Plasmodium chabaudi infection. CD4+ memory T cells (CD44hiIL-7Rα+) developed during the chronic infection, and were readily distinguishable from effector (CD62LloIL-7Rα−) cells in acute infection. On the basis of cell surface phenotype, we classified memory CD4+ T cells into three subsets: central memory, and early and late effector memory cells, and found that early effector memory cells (CD62LloCD27+) dominated the chronic infection. We demonstrate a linear pathway of differentiation from central memory to early and then late effector memory cells. In adoptive transfer, CD44hi memory cells from chronically infected mice were more effective at delaying and reducing parasitemia and pathology than memory cells from drug-treated mice without chronic infection, and contained a greater proportion of effector cells producing IFN-γ and TNFα, which may have contributed to the enhanced protection. These findings may explain the observation that in humans with chronic malaria, activated effector memory cells are best maintained in conditions of repeated exposure

Representações políticas do território latino-americano na Revista Seleções

Este artigo tem por objetivo analisar as representações sobre a América Latina construídas pela revista Seleções do Reader's Digest, entre 1942 e 1970, e mostra como essas representações estiveram informadas pela idéia de wilderness, profundamente enraizada no imaginário norte-americano.This article intends to analyse the representations about Latin America produced by Seleções do Reader's Digest magazine, from 1942 to 1970. It demonstrates that these representations were influenced by wilderness imaginary, which is deeply rooted in North American culture

Ciência, técnica e as expedições da marinha de guerra norteamericana, U.S. Navy, em direção à América Latina (1838-1901) Science, techniques, and U.S. naval expeditions toward Latin America (1838-1901)

Este artigo tem por objetivo mapear as expedições realizadas pela U. S. Navy - a marinha de guerra dos Estados Unidos - em direção à América Latina, no século XIX. Foram realizadas doze viagens no período, mostrando o interesse norte-americano pela região desde a década de 1830.<br>This article focuses on U.S. Navy expeditions set a course from United States to Latin America in nineteenth century. Twelve expeditions as a whole were accomplished in that period, showing the American concern in that region, since 1830 decade