Sequência didática como instrumento para a aprendizagem significativa do efeito fotoelétrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hidrólise enzimática de fibra de Caroá (Neoglaziovia variegata) visando à produção de nanocelulose e etanol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção de etanol utilizando cascas de banana e de laranja por co-fermentação de Zymomonas mobilis e Pichia stipitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modelagem da irradiação direta na incidência normal em Botucatu: aprendizado de máquina, estatístico e linke

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Analysis of plant LTR-retrotransposons at the fine-scale family level reveals individual molecular patterns

Background: Sugarcane is an important crop worldwide for sugar production and increasingly, as a renewable energy source. Modern cultivars have polyploid, large complex genomes, with highly unequal contributions from ancestral genomes. Long Terminal Repeat retrotransposons (LTR-RTs) are the single largest components of most plant genomes and can substantially impact the genome in many ways. It is therefore crucial to understand their contribution to the genome and transcriptome, however a detailed study of LTR-RTs in sugarcane has not been previously carried out. Results: Sixty complete LTR-RT elements were classified into 35 families within four Copia and three Gypsy lineages. Structurally, within lineages elements were similar, between lineages there were large size differences. FISH analysis resulted in the expected pattern of Gypsy/heterochromatin, Copia/euchromatin, but in two lineages there was localized clustering on some chromosomes. Analysis of related ESTs and RT-PCR showed transcriptional variation between tissues and families. Four distinct patterns were observed in sRNA mapping, the most unusual of which was that of Ale1, with very large numbers of 24nt sRNAs in the coding region. The results presented support the conclusion that distinct small RNA-regulated pathways in sugarcane target the lineages of LTR-RT elements. Conclusions: Individual LTR-RT sugarcane families have distinct structures, and transcriptional and regulatory signatures. Our results indicate that in sugarcane individual LTR-RT families have distinct behaviors and can potentially impact the genome in diverse ways. For instance, these transposable elements may affect nearby genes by generating a diverse set of small RNA's that trigger gene silencing mechanisms. There is also some evidence that ancestral genomes contribute significantly different element numbers from particular LTR-RT lineages to the modern sugarcane cultivar genome.

Life Cycle Assessment of Peach Nectar: a comparative analysis between conventional and bioenergy-from-waste integrated food chains

Modern food systems are characterized by a high energy intensity as well as by the production of large amounts of waste, residuals and food losses. This inefficiency presents major consequences, in terms of GHG emissions, waste disposal, and natural resource depletion. The research hypothesis is that residual biomass material could contribute to the energetic needs of food systems, if recovered as an integrated renewable energy source (RES), leading to a sensitive reduction of the impacts of food systems, primarily in terms of fossil fuel consumption and GHG emissions. In order to assess these effects, a comparative life cycle assessment (LCA) has been conducted to compare two different food systems: a fossil fuel-based system and an integrated system with the use of residual as RES for self-consumption. The food product under analysis has been the peach nectar, from cultivation to end-of-life. The aim of this LCA is twofold. On one hand, it allows an evaluation of the energy inefficiencies related to agro-food waste. On the other hand, it illustrates how the integration of bioenergy into food systems could effectively contribute to reduce this inefficiency. Data about inputs and waste generated has been collected mainly through literature review and databases. Energy balance, GHG emissions (Global Warming Potential) and waste generation have been analyzed in order to identify the relative requirements and contribution of the different segments. An evaluation of the energy “loss” through the different categories of waste allowed to provide details about the consequences associated with its management and/or disposal. Results should provide an insight of the impacts associated with inefficiencies within food systems. The comparison provides a measure of the potential reuse of wasted biomass and the amount of energy recoverable, that could represent a first step for the formulation of specific policies on the integration of bioenergies for self-consumption.

Efeitos da mecanização agrícola da cultura da cana-de-açúcar nos processos erosivos: dimensionamento de terraços com base na Equação Universal de Perdas de Solo (EUPS)

A cultura da cana-de-açúcar é a segunda maior movimentação econômica na cadeia do agronegócio no Brasil. Gera riquezas através da fabricação de açúcar, etanol e cogeração de energia elétrica, além de outros subprodutos. Considerada fonte de energia renovável, a cana-de- açúcar a princípio tinha sua imagem associada a impactos negativos principalmente devido as queimadas realizadas nas lavouras para colheita manual. Nos últimos anos, baseado em decretos e no Protocolo Agro-ambiental, essa prática vem sendo abolida. Para se manter e até mesmo aumentar o rendimento das colhedoras nos canaviais, os gestores têm adotado práticas para reduzir os terraços agrícolas, com impacto nos sistemas de conservação de solos. Assim, este trabalho teve como objetivo identificar os impactos ambientais provocados pela mecanização agrícola decorrente do mau manejo e dimensionamento dos mecanismos de conservação do solo. Neste estudo também se realizou uma análise à Equação Universal de Perdas de Solo (EUPS), como ferramenta para o dimensionamento de terraços agrícolas. O estudo foi realizado em uma microbacia hidrográfica, denominada Ribeirão da Bocaina, localizada na UGRHI-13 (Tietê - Jacaré). Foi possível identificar a variabilidade amostral do solo para o dimensionamento conservacionista, gerando curvas de nível com Desníveis Verticais (D.V) desuniformes, contrariando a sistemática atual de terraços que respeita cotas múltiplas ou mesmo dimensionamentos empiristas, segundo o conhecimento local e o histórico recente da área. Algumas sugestões também foram feitas afim de torná-la uma ferramenta ainda mais eficiente, considerando condições particulares à cultura da cana-de-açúcar, tais como a influência da palhada, sulcos de plantio e diversos tipos de terraços como meios de controle à erosão. A metodologia foi satisfatória, no que tange a compreensão pelos meios de correlação entre as práticas conservacionistas e modelos de predição de perda de solo, trazendo luz à ciência na interpretação das ferramentas existentes e as lacunas a serem preenchidas.

Efeito da adição de fibras de cana-de-açúcar pré-tratadas na produção de metano advinda da biodigestão anaeróbia de gorduras do leite

A digestão anaeróbia é uma alternativa para o tratamento de resíduos com altas concentrações de matéria orgânica. Por meio dos processos anaeróbios é possível a produção de biogás, fonte de energia renovável e ambientalmente amigável. Elevadas concentrações de lipídios, todavia, apesar de representarem elevado potencial metanogênico, interferem negativamente nos sistemas de tratamento, podendo inibir a atividade microbiana e, consequentemente, a produção de metano. O presente projeto avaliou o efeito da adição de bagaço de cana-de-açúcar no processo de biodigestão anaeróbia de elevadas concentrações de gorduras advindas de efluentes de laticínio. Para tanto foi utilizado bagaço de cana-de-açúcar in natura e pré-tratadas pelos seguintes métodos: organossolve, hidrotérmico, explosão à vapor e ácido diluído. O uso desse material lignocelulósico teve o objetivo de controlar a inibição causada pelos produtos da hidrólise dos lipídios por meio de sua adsorção e, consequentemente, diminuição das concentrações de tais compostos no meio. Outra hipótese era que o bagaço de cana-de-açúcar pudessem agir como co-substrato no processo de biodigestão anaeróbia. Inicialmente realizaram-se ensaios de biodegradabilidade anaeróbia com concentrações crescentes de gordura, que resultaram em relação entre substrato e microrganismo 0,06, 0,1, 0,2, 0,4 e 0,6 g DQO/gSTV. O ensaio com concentração em que foi verificada a inibição severa (0,4 gDQO/gSTV) do processo foi repetido com adição das fibras tratadas e não tratadas. Aos dados de produção acumulada de metano ajustou-se modelo de Gompertz, e parâmetros cinéticos foram inferidos. O bagaço de cana-de-açúcar mostrou potencial como adsorvente de gordura, pois as produções metanogênicas foram superiores à condição inibida sem adição desse material. A adição de fibras pré-tratadas por método organossolve resultou nas maiores produções de metano.

Block copolymer strategies for solar cell technology

A simple overview of the methods used and the expected benefits of block copolymers in organic photovoltaic devices is given in this review. The description of the photovoltaic process makes it clear how the detailed self-assembly properties of block copolymers can be exploited. Organic photovoltaic technology, an inexpensive, clean and renewable energy source, is an extremely promising option for replacing fossil fuels. It is expected to deliver printable devices processed on flexible substrates using high-volume techniques. Such devices, however, currently lack the long-term stability and efficiency to allow organic photovoltaics to surpass current technologies. Block copolymers are envisaged to help overcome these obstacles because of their long term structural stability and their solid-state morphology being of the appropriate dimensions to efficiently perform charge collection and transfer to electrodes.

Applications of Photoinduced Electron Transfer Chemistry: Photoremovable Protecting Groups and Carbon Dioxide Conversion

Traditional organic chemistry has long been dominated by ground state thermal reactions. The alternative to this is excited state chemistry, which uses light to drive chemical transformations. There is considerable interest in using this clean renewable energy source due to concerns surrounding the combustion byproducts associated with the consumption of fossil fuels. The work presented in this text will focus on the use of light (both ultraviolet and visible) for the following quantitative chemical transformations: (1) the release of compounds containing carboxylic acid and alcohol functional groups and (2) the conversion of carbon dioxide into other useable chemicals. Chapters 1-3 will introduce and explore the use of photoremovable protecting groups (PPGs) for the spatiotemporal control of molecular concentrations. Two new PPGs are discussed, the 2,2,2-tribromoethoxy group for the protection of carboxylic acids and the 9-phenyl-9-tritylone group for the protection of alcohols. Fundamental interest in the factors that affect C–X bond breaking has driven the work presented in this text for the release of carboxylic acid substrates. Product analysis from the UV photolysis of 2,2,2-tribromoethyl-(2′-phenylacetate) in various solvents results in the formation of H–atom abstraction products as well as the release of phenylacetic acid. The deprotection of alcohols is realized through the use of UV or visible light photolysis of 9-phenyl-9-tritylone ethers. Central to this study is the use of photoinduced electron transfer chemistry for the generation of ion diradicals capable of undergoing bond-breaking chemistry leading to the release of the alcohol substrates. Chapters 4 and 5 will explore the use of N-heterocyclic carbenes (NHCs) as a catalyst for the photochemical reduction of carbon dioxide. Previous experiments have demonstrated that NHCs can add to CO2 to form stable zwitterionic species known as N-heterocylic-2-carboxylates (NHC–CO2). Work presented in this text illustrate that the stability of these species is highly dependent on solvent polarity, consistent with a lengthening of the imidazolium to carbon dioxide bond (CNHC–CCO2). Furthermore, these adducts interact with excited state electron donors resulting in the generation of ion diradicals capable of converting carbon dioxide into formic acid.

Avaliação do potencial energético de cana (Arundo donax L.) no Algarve

Dissertação de Mestrado, Energias Renováveis e Gestão de Energia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016

Análise de um queimador infravermelho funcionando com combustível híbrido : GLP/Bio-óleo

Biomass is considered the largest renewable energy source that can be used in an environmentally sustainable. From the pyrolysis of biomass is possible to obtain products with higher energy density and better use properties. The liquid resultant of this process is traditionally called bio-oil. The use of infrared burners in industrial applications has many advantages in terms of technical-operational, for example, uniformity in the heat supply in the form of radiation and convection, with a greater control of emissions due to the passage of exhaust gases through a macroporous ceramic bed. This paper presents a commercial infrared burner adapted with an ejector proposed able to burn a hybrid configuration of liquefied petroleum gas (LPG) and bio-oil diluted. The dilution of bio-oil with absolute ethanol aimed to decrease the viscosity of the fluid, and improving the stability and atomization. It was introduced a temperature controller with thermocouple modulating two stages (low heat / high heat), and solenoid valves for fuels supply. The infrared burner has been tested, being the diluted bio-oil atomized, and evaluated its performance by conducting energy balance. The method of thermodynamic analysis to estimate the load was used an aluminum plate located at the exit of combustion gases and the distribution of temperatures measured by thermocouples. The dilution reduced the viscosity of the bio-oil in 75.4% and increased by 11% the lower heating value (LHV) of the same, providing a stable combustion to the burner through the atomizing with compressed air and burns combined with LPG. Injecting the hybrid fuel there was increase in the heat transfer from the plate to the environment in 21.6% and gain useful benefit of 26.7%, due to the improved in the efficiency of the 1st Law of Thermodynamics of infrared burner

Hierarchical energy management system for multi-source multi-product microgrids

This paper proposes a hierarchical energy management system for multi-source multi-product (MSMP) microgrids. Traditional energy hub based scheduling method is combined with a hierarchical control structure to incorporate transient characteristics of natural gas flow and dynamics of energy converters in microgrids. The hierarchical EMS includes a supervisory control layer, an optimizing control layer, and an execution control layer. In order to efficiently accommodate the systems multi time-scale characteristics, the optimizing control layer is decomposed into three sub-layers: slow, medium and fast. Thermal, gas and electrical management systems are integrated into the slow, medium, and fast control layer, respectively. Compared with wind energy, solar energy is easier to integrate and more suitable for the microgrid environment, therefore, potential impacts of the hierarchical EMS on MSMP microgrids is investigated based on a building energy system integrating photovoltaic and microturbines. Numerical studies indicate that by using a hierarchical EMS, MSMP microgrids can be economically operated. Also, interactions among thermal, gas, and electrical system can be effectively managed.

Evaluation of resonant damping techniques for Z-source current-type inverter

For the renewable energy sources whose outputs vary continuously, a Z-source current-type inverter has been proposed as a possible buck-boost alternative for grid-interfacing. With a unique X-shaped LC network connected between its dc power source and inverter topology, Z-source current-type inverter is however expected to suffer from compounded resonant complications in addition to those associated with its second-order output filter. To improve its damping performance, this paper proposes the careful integration of Posicast or three-step compensators before the inverter pulse-width modulator for damping triggered resonant oscillations. In total, two compensators are needed for wave-shaping the inverter boost factor and modulation ratio, and they can conveniently be implemented using first-in first-out stacks and embedded timers of modern digital signal processors widely used in motion control applications. Both techniques are found to damp resonance of ac filter well, but for cases of transiting from current-buck to boost state, three-step technique is less effective due to the sudden intermediate discharging interval introduced by its non-monotonic stepping (unlike the monotonic stepping of Posicast damping). These findings have been confirmed both in simulations and experiments using an implemented laboratory prototype.

Doubly Fed Induction Generator for wind energy generation using nine-switch power converter

A Three-Phase Nine-Switch Converter (NSC) topology for Doubly Fed Induction Generator in wind energy generation is proposed in this paper. This converter topology was used in various applications such as Hybrid Electric Vehicles and Uninterruptable Power Supplies. In this paper, Nine-Switch Converter is introduced in Doubly Fed Induction Generator in renewable energy application for the first time. It replaces the conventional Back-to-Back Pulse Width Modulated voltage source converter (VSC) which composed of twelve switches in many DFIG applications. Reduction in number of switches is the most beneficial in terms of cost and power switching losses. The operation principle of Nine-Switch Converter using SPWM method is discussed. The resulting NSC performance of rotor side current control, active power and reactive control are compared with Back-to Back voltage source converter performance. DC link voltage regulation using front end converter is also presented. Finally the simulation results of DFIG performances using NSC and Back-to-Back VSC are analyzed and compared.