Renewable energy has been developing rapidly in the U.S. over the past decades. This thesis first reviewed the status, challenges, and government policies related to the development of bioenergy products from forest-derived woody biomass. Forest management alternatives of loblolly pine (Pinus taeda) plantations for producing both timber and biofuels were then evaluated using economic and biological criteria. The PTAEDA3.1 computerized yield simulator was used to predict growth effects of various site preparation techniques, initial planting densities, and thinning activity. Results indicated that on Site Index 50 to 70 lands, the average annual yields of stem residues ranged from 0.86 to 1.20 tons per acre, from which 39.8 to 47.4 gallons of ethanol could be produced. The rise of relative biomass price would increase wood availability for biofuels. It will also boost intensive management practices, such as intensive site preparation, closer initial planting spacing, earlier thinnings and a shorter harvesting age.

Orientador: Sandra Imaculada Maintinguer / Resumo: A bioconversão de diferentes materiais orgânicos em hidrogênio é uma tecnologia sustentável. Inóculos de climas tropicais, como o Brasil, com temperaturas médias de 25°C podem favorecer o crescimento bacteriano. A geração de hidrogênio com consórcios bacterianos têm vantagens sobre culturas puras quanto aplicado no tratamento de águas residuárias. O hidrogênio pode ser gerado em duas fases durante os processos anaeróbios. Em primeiro lugar, hidrogênio e ácidos orgânicos podem ser produzidos por processos fermentativos. Esses ácidos gerados podem ser usados por bactérias fotoheterotróficas na segunda fase, durante a operação dos reatores anaeróbios na presença de luz. O objetivo deste estudo foi avaliar o potencial de produção hidrogênio a partir de resíduos orgânicos por consórcios de bactérias fotoheterotróficas. Foram feitos 12 ensaios (I-XII) separadamente, em triplicatas de reatores anaeróbios em batelada, em meio de cultivo Rhodospirillaceae, headspace N2 (100%), pH 7.0+1, a 37ºC. Foram comprovados os efeitos com duas potências de intensidade de luz (8,8±1 e 18,5±1 W/m2) e diferentes concentrações de ácidos butírico, acético, além de efluentes de processos fermentativos procedentes de glicerol bruto e águas residuárias citrícolas. As condições ótimas para a produção de hidrogênio foram de 18.5±1 W/m2 de intensidade de luz e 1.7 g/L para o ácido acético (II), 1.0 g/L para o ácido butírico (V), 1.0 g de COD/L de glicerol efluente (IX), e 0.5 g de DQO/L para o efluente de á... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The bioconversion of different organic materials to hydrogen is a sustainable technology. Inocula from tropical climates such as Brazil which average temperatures around 25°C may favour the bacterial growth. Hydrogen generation with bacterial consortia have advantages over pure cultures regarding application to wastewater treatment. The hydrogen can be generates in two stages during the anaerobic processes. Firstly, hydrogen and organic acids can be produced by dark fermentation. The acids generated during the first stage of the fermentation process can be used by phototrophic bacteria in the second stage during the operation of anaerobic batch reactors on the light presence. The aim of this study was evaluate the hydrogen producing potential from organic wastes by phototrophic bacterial consortia. Assays (I - XII) were made separately in triplicates of anaerobic batch reactors, Rhodospirillaceae medium (Chi Mei Lee, 2005), headspace with N2 (100%), pH 7.0+1, at 37oC. Effects with two potencies of light intensity (8.8±1 and 18.5±1 W/m2 ) and different concentrations of butyric acid, acetic acid and dark fermentation effluents from crude glycerol and citrus wastewaters were optimized. The optimal conditions for hydrogen production from phototrophic consortia were 18.5±1 W/m2 of light intensity and 1.7 g/L for acetic acid (II), 1.0 g/L for butyric acid (V), 1.0 g COD/L for Glycerol effluent (IX), and 0.5 g COD/L for citrus wastewater effluent (XII). Under the optimum conditions... (Complete abstract click electronic access below) / Mestre

The subject of my assignment is the direct sale of bio production. The main subject of my assignment was to find out consumer interest in selling bio products, respectively, for direct sales of bio production. Another objective was to analyze the current status of direct sales of bio production in South Bohemia region. The first point of assignment I have met on the base of consumer research using a questionnaire created in the application Google docs. My research showed that the use of direct purchase is used more women. The most common reason why women don{\crq}t like the direct purchase is little information. Most of the men don{\crq}t use direct purchase, because of lack of time and little information. The interests about direct sale have more woman than men. The main reason of woman why to use direct purchase is that they think that bio products from producer are fresher and trust that bio product is really bio. The most of the men will be interest it in direct sale because of freshness of bio products. The convenience of men is the main reason why they don{\crq}t use direct purchase. Women as a reason for disinterest reported lack of time The second research was focused on South Bohemia ECO farms. In total were asked 64 ECO farms, only 50 take part in. For bio farms engaged in cattle breeding is 32% of sales secured by sales of meat, live animals on the farms or own in shop. In other commodities grown on ECO farms in South Bohemia region have direct sale of their production only two milk companies. In commodities of fruit, cereals, forage legume and potatoes, none of the companies don{\crq}t have direct sale of own production.