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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

CELLULOSE NANOCRYSTALS AND RELATED POLYMER NANOCOMPOSITES

Cudjoe, Elvis 06 September 2017 (has links)
No description available.
52

Arthropod Abundance and Diversity in Miscanthus x giganteus, Panicum virgatum, and Other Habitat Types in Southeastern Ohio

Snelick, Taylor L. 13 July 2018 (has links)
No description available.
53

Cultiver Miscanthus x giganteus en parcelles agricoles : du diagnostic agro-environnemental à la conception-évaluation ex ante de systèmes de culture à vocation énergétique / Cropping Miscanthus x giganteus in commercial fields : from agro-environmental diagnostic to ex ante design and assessment of energy oriented cropping systems

Lesur, Claire 21 December 2012 (has links)
Second-generation biofuels could provide renewable energy while reducing the globaleconomy dependence on oil and mitigating climate change. However, their greenhouse gasemission balances, as well as their energy and environmental balances, are discussed,especially when they are produced from agricultural feedstock. The use of agriculturalfeedstock for energy purposes also raises the issue of competition with food production. Inthis context, this work contributes to the assessment of the sustainability of Miscanthus xgiganteus, a perennial C4 crop candidate to the production of second-generation ethanol. Theobjectives of this work are (i) to achieve a multicriteria evaluation of cropping systems basedon M. Giganteus using data collected in farmers’ fields and (ii) to compare these croppingsystems with cropping systems including other resources Agricultural candidates for biofuelproduction. The main contributions of this work are (i) the study of the variability of yieldsand winter nitrate losses in a network of commercial fields located in Burgundy (France), (ii)the characterization by modeling of M. giganteus long-term yield evolution and (iii) theintegration of these findings in a process of cropping systems design and assessment aimingat comparing M. giganteus with other feedstock candidate to the production of bioethanol.The study of M. giganteus in farmers’ fields shows that the high variability of yields andnitrate losses is linked to (i) crop age, (ii) soil type and (iii) the type of field (i.e. culturalhistory, size, shape, and environment). Contrasting yield scenarios, built by combining datacollected in commercial fields with a long-term yield evolution model, show that thesensitivity of assessment results regarding yields depends on the assessment field. Theinsertion of M. giganteus in a cropping system can significantly improve the greenhouse gasemission balance as well as the environmental balance, compared with a cropping systembased on a short cropping sequence. Economic results depend strongly on M. giganteus yield.Other agricultural feedstocks are also interesting, especially on soils where the yield potentialof M. giganteus is low: this is particularly the case of alfalfa stems, which can be used forsecond-generation ethanol production. / Second-generation biofuels could provide renewable energy while reducing the globaleconomy dependence on oil and mitigating climate change. However, their greenhouse gasemission balances, as well as their energy and environmental balances, are discussed,especially when they are produced from agricultural feedstock. The use of agriculturalfeedstock for energy purposes also raises the issue of competition with food production. Inthis context, this work contributes to the assessment of the sustainability of Miscanthus xgiganteus, a perennial C4 crop candidate to the production of second-generation ethanol. Theobjectives of this work are (i) to achieve a multicriteria evaluation of cropping systems basedon M. Giganteus using data collected in farmers’ fields and (ii) to compare these croppingsystems with cropping systems including other resources Agricultural candidates for biofuelproduction. The main contributions of this work are (i) the study of the variability of yieldsand winter nitrate losses in a network of commercial fields located in Burgundy (France), (ii)the characterization by modeling of M. giganteus long-term yield evolution and (iii) theintegration of these findings in a process of cropping systems design and assessment aimingat comparing M. giganteus with other feedstock candidate to the production of bioethanol.The study of M. giganteus in farmers’ fields shows that the high variability of yields andnitrate losses is linked to (i) crop age, (ii) soil type and (iii) the type of field (i.e. culturalhistory, size, shape, and environment). Contrasting yield scenarios, built by combining datacollected in commercial fields with a long-term yield evolution model, show that thesensitivity of assessment results regarding yields depends on the assessment field. Theinsertion of M. giganteus in a cropping system can significantly improve the greenhouse gasemission balance as well as the environmental balance, compared with a cropping systembased on a short cropping sequence. Economic results depend strongly on M. giganteus yield.Other agricultural feedstocks are also interesting, especially on soils where the yield potentialof M. giganteus is low: this is particularly the case of alfalfa stems, which can be used forsecond-generation ethanol production.
54

Nouvelles enzymes fongiques pour l'amélioration de la dégradation de la biomasse lignocellulosique : étude des "Lytic Polysaccharide Monooxygenases" (LPMOs) / New fungal enzymes for the improvement of lignocellulosic biomass degradation : study of the "Lytic Polysaccharide Monooxygenases" (LPMOs)

Bennati-Granier, Chloe 02 February 2016 (has links)
Dans le contexte actuel, il devient nécessaire de rendre les alternatives au pétrole, tel que le bioéthanol 2G, disponibles à grande échelle. Cependant, l’étape d’hydrolyse par les enzymes de Trichoderma reesei reste un verrou à un procédé économiquement stable et rentable. Ces travaux de thèse, s'intègrent dans le cadre du projet Futurol et ont pour objectifs d'identifier et de caractériser de nouvelles enzymes fongiques pour améliorer l'hydrolyse de la biomasse lignocellulosique. A partir des données protéomiques disponibles pour Podospora anserina et Fusarium verticillioides, une douzaine d'enzymes candidates ont été identifiées dans leurs sécrétomes. Ce travail de thèse s'est plus particulièrement focalisé sur les AA9s « Lytic Polysaccharide Monooxygenases » (LPMOs) de P. anserina. Parmi les LPMOs étudiées, PaLPMO9A, PaLPMO9E et PaLPMO9H, qui possèdent un CBM1, sont les plus actives sur la cellulose. La détermination de la régiosélectivité d'action a mis en évidence que PaLPMO9A et PaLPMO9H clivent la cellulose en position C1 et C4 alors que la PaLPMO9E génère uniquement des produits oxydés en C1. La PaLPMO9H est la plus versatile puisqu’elle est active sur les cello-oligosaccharides solubles et sur les polysaccharides hémicellulosiques liés en β-(1,4) (i.e., xyloglucane, glucomannane). La supplémentation du cocktail de T. reesei avec PaLPMO9E ou PaLPMO9H a permis de doubler les rendements d'hydrolyse du miscanthus prétraité. Les travaux réalisés au cours de cette thèse ont permis de démontrer l'importance de ces enzymes oxydatives dans les phénomènes de déconstruction de la lignocellulose chez les champignons filamenteux. / In the current context, it becomes essential to make alternative to oil, such as the 2G bioethanol, available at large scale. However, the hydrolysis step by Trichoderma reesei enzymes remains the major bottleneck for an economically sustainable process. The present work is part of the Futurol project, and aims at identifying and characterizing new fungal enzymes to improve the hydrolysis of lignocellulosic biomass. From the proteomic data available for Podospora anserina and Fusarium verticillioides, a dozen of interesting enzymes were identified in their secretomes. This work focuses, mainly, on the AA9s « Lytic Polysaccharide Monooxygenases » (LPMOs) from P. anserina. Among all the LPMOs studied, PaLPMO9A, PaLPMO9E and PaLPMO9H that harbored a CBM1 were the most active on cellulose. Investigation of their regioselective mode of action revealed that PaLPMO9A and PaLPMO9H oxidatively cleaved at both C1 and C4 positions while PaLPMO9E released only C1-oxidized products. PaLPMO9H that was the most versatile in terms of substrate specificity as it also displayed activity on cello-oligosaccharides and β-(1,4)-linked hemicellulose polysaccharides (e.g., xyloglucan, glucomannan). The hydrolysis yield of the pretreated miscanthus was significantly improved up to 2 fold, when the PaLPMO9E, or PaLPMO9H were supplemented to the T. reesei cocktail. This work demonstrated the importance of these oxidative enzymes for lignocellulose deconstruction by fungi. These biocatalysts open new prospects to improve the enzymatic conversion of plant biomass for 2G bioethanol production.
55

Patterns and process : biodiversity and ecosystem function response to changes in the arable landscape

Berkley, Nicholas Alexander James January 2018 (has links)
Land use change is a major driver of species loss worldwide, the extent and intensity of agricultural land use poses particular pressures for biodiversity and the ecosystem services it provides. In recent years, agroecosystems have seen the introduction of 2nd generation bioenergy crops in order to tackle anthropogenic climate change, providing a renewable alternative to fossil fuels. In this thesis I study the impact of cultivating two commercial perennial energy crops (PECs), Miscanthus x giganteus and willow short-rotation coppice, when compared to the cereal crops they replace. I investigate processes relevant to the provisioning of pollination and decomposition services and explore patterns of soil element bioaccessibility alongside analyses of the similarity and diversity of soil bacterial communities. When compared to cereals, I find a consistent increase in pollinator (hoverfly, bumblebee and butterfly/moth) wildflower visitation in the margins of willow but not Miscanthus. In Miscanthus, opposing trends arose for different pollinator taxa: butterflies/moths were more frequent flower visitors in Miscanthus margins than cereal margins, while hoverfly flower visits were most frequent in cereal margins. Furthermore, the availability of margin wildflowers was enhanced in willow but not Miscanthus and the seed set of margin phytometers was similar between Miscanthus and cereals. Cultivation of willow, in particular, may therefore yield local conservation benefits for both wildflowers and pollinators. However, there was no evidence for enhancement of pollinator activity in cereals adjacent to either PEC, indicating that the strategic cultivation of these crops is unlikely to enhance pollinator service provision in the wider agri-environment. For investigated soil elements, bioaccessibility in PECs did not differ significantly to cereal controls, and denaturing gradient gel electrophoresis (DGGE) revealed no difference in the diversity of bacterial communities. Similarly, DGGE fingerprint patterns did not indicate the development of crop specific assemblages, demonstrating that the mobility of soil elements and structure of bacterial communities were principally determined by factors other than the identity of the crop cultivated. Investigation of meso-microfaunal decomposition rates in Miscanthus using litter bags demonstrated an impact on decomposition processes, with a significant increase in winter decomposition rates in the PEC when compared to cereals.
56

Žolinių augalų panaudojimas kietajam biokurui / Herbal plants use for solid biofuel

Navadvorskytė, Justina 04 February 2013 (has links)
Šio magistro baigiamojo darbo tikslas buvo ištirti trijų energetinių žolinių augalų biometrines bei energetines savybes ir jas palyginti tarpusavyje. Augalai buvo auginami lauko sąlygomis, kiekvieną augalą tręšiant skirtingomis mineralinio azoto normomis (N0 – kontrolė, N60 – 200 kg ha-1 ir N120 – 400 kg ha-1). Buvo tiriami pagrindiniai biometriniai rodikliai: augalų aukštis, augalų stiebų skaičius, sausoji biomasė, chlorofilo indeksas. Taip pat ištirtas pasirinktų augalų šilumingumas, peleningumas, pagrindiniai elementai (C, H, N, S, O) bei šalutiniai elementai (K, Ca, Mg, P, Al, Si, S), taip pat sunkieji metalai. Visų augalų energetinės savybės palygintos tarpusavyje. Vertinant gautus duomenis, tinkamiausi žoliniai augalai biokurui yra sida ir drambliažolė, kadangi jų peleningumas yra mažiausias. Tačiau nendrinio dryžučio, nors ir išsiskyrė didesniu peleningumu, šilumingumas buvo didžiausias. Cheminės sudėties analizės metu buvo nustatyta, jog papildomas tręšimas azotinėmis trąšomis įvairių elementų kiekiui augaluose didelės įtakos neturėjo, tačiau vertinant šalutinių elementų kiekį augaluose pastebėta tai, jog kai kurių cheminių elementų padidėjimą galėjo lemti ir augalų augimo vieta (atvira pieva, šalia žvyrkelio, šalia kelio, šalia dirbamo lauko ir pan.). / This master's thesis was to analyze three energy plant grass biometric and energy properties and to compare them with each other. Plants were grown in field, every plant fertilized with different rates of nitrogen (N0 - control, N60 - 200 kg ha-1 and N120 - 400 kg ha-1). It was investigated the main biometric parameters: plant height, plant stems, dry biomass and chlorophyll index. Also plants calorific value, ash content, the main elements (C, H, N, S, O) and minor elements (K, Ca, Mg, P, Al, Si, S) and heavy metals. Plant‘s energy properties were compared with each other. Evaluating the data, the optimum herbaceous plant for biofuels are sida and Miscanthus as their ash content is lowest. Reed canary grass calorific value was highest, but it stood higher ash content too. Chemical composition analysis showed that the additional nitrogen fertilization had no major impact of the various elements in plants, but by assessing the amount of elements in plants is noticeable that plant growth and position may impact some chemical elements increase (open meadow, near the gravel, next to the road, arable land, etc.).
57

Žolinių augalų panaudojimas kietajam biokurui / Herbal plants use for solid biofuel

Navadvorskytė, Justina 04 February 2013 (has links)
Šio magistro baigiamojo darbo tikslas buvo ištirti trijų energetinių žolinių augalų biometrines bei energetines savybes ir jas palyginti tarpusavyje. Augalai buvo auginami lauko sąlygomis, kiekvieną augalą tręšiant skirtingomis mineralinio azoto normomis (N0 – kontrolė, N60 – 200 kg ha-1 ir N120 – 400 kg ha-1). Buvo tiriami pagrindiniai biometriniai rodikliai: augalų aukštis, augalų stiebų skaičius, sausoji biomasė, chlorofilo indeksas. Taip pat ištirtas pasirinktų augalų šilumingumas, peleningumas, pagrindiniai elementai (C, H, N, S, O) bei šalutiniai elementai (K, Ca, Mg, P, Al, Si, S), taip pat sunkieji metalai. Visų augalų energetinės savybės palygintos tarpusavyje. Vertinant gautus duomenis, tinkamiausi žoliniai augalai biokurui yra sida ir drambliažolė, kadangi jų peleningumas yra mažiausias. Tačiau nendrinio dryžučio, nors ir išsiskyrė didesniu peleningumu, šilumingumas buvo didžiausias. Cheminės sudėties analizės metu buvo nustatyta, jog papildomas tręšimas azotinėmis trąšomis įvairių elementų kiekiui augaluose didelės įtakos neturėjo, tačiau vertinant šalutinių elementų kiekį augaluose pastebėta tai, jog kai kurių cheminių elementų padidėjimą galėjo lemti ir augalų augimo vieta (atvira pieva, šalia žvyrkelio, šalia kelio, šalia dirbamo lauko ir pan.). / This master's thesis was to analyze three energy plant grass biometric and energy properties and to compare them with each other. Plants were grown in field, every plant fertilized with different rates of nitrogen (N0 - control, N60 - 200 kg ha-1 and N120 - 400 kg ha-1). It was investigated the main biometric parameters: plant height, plant stems, dry biomass and chlorophyll index. Also plants calorific value, ash content, the main elements (C, H, N, S, O) and minor elements (K, Ca, Mg, P, Al, Si, S) and heavy metals. Plant‘s energy properties were compared with each other. Evaluating the data, the optimum herbaceous plant for biofuels are sida and Miscanthus as their ash content is lowest. Reed canary grass calorific value was highest, but it stood higher ash content too. Chemical composition analysis showed that the additional nitrogen fertilization had no major impact of the various elements in plants, but by assessing the amount of elements in plants is noticeable that plant growth and position may impact some chemical elements increase (open meadow, near the gravel, next to the road, arable land, etc.).
58

Pěstování vybraných energetických plodin výnosové parametry / Growing of energy crops - yield parameters

NĚMEC, Václav January 2014 (has links)
Thesis deals with renewables resources, potential of biomass and plants phytomass. We focused on the cultivation of selected energy crops, as perennial grasses Elymus elongatus (subsp. ponticus, cv. Szarvasi-1), reed canary grass, miscanthus sinensis and annual crops of maize and sorghum. The practical part is aimed to the establishment of small plot trials with a variety Szarvasi-1, reed canary grass and miscanthus. We described the methods of field experiment establishing with crop Szarvasi-1 of their treatment and harvest. The results of our own experiments we compared with the literature data. The last part deals with the economy of growing selected crops.
59

Pěstování vybraných druhů rostlin pro energetické využití

ŠVEC, Miroslav January 2018 (has links)
This diploma thesis on the topic "Cultivation of selected plant species for energy use" in the first chapters of the theoretical part deals with Czech and world energy. The chapters on renewable energy sources and the possibilities of using biomass for plants for energy purposes follow. The research also deals with grasslands as alternative energy sources with a focus on direct burning. The last chapters of the research are focused on the cultivation of selected energy crops, such as the Elymus elongatus grass (subspecies Ponticus, Szarvasi-1) and Miscanthus × giganteus. The practical part describes the establishment, nursing and harvesting of small-scale experiments of Szarvasi-1 grass and Miscanthus × giganteus grass varieties, which were cultivated on the premises of the University of South Bohemia in České Budějovice and were grown as energy crops for direct incineration. Experiments with the Szarvas-1 cultivation took place in three types of farming. The first variation was the so-called "extensive" form where the plants were not fertilized with any fertilizer. The second form of farming was the "intensive" variant, in which the fertilizer was fertilized with mineral fertilizers. The last variant labeled "digestate" was fertilized with organic fertilizer. Maloparcelian experiments with Miscanthus × giganteus were carried out only in one variation of cultivation than Szarvasi-1, "intensive". For both varieties of energy crops harvested in spring 2013 and for all cultivation variants, the yield potentials from the last five years of vegetation of these cultures were evaluated after a six-year vegetation period. The evaluated parameters were in particular the yields of fresh matter and dry matter in t ha-1, but also the average solids content in %. These results were recorded and compared with specialist literature. The results of the work show that Miscanthus × giganteus yields on average higher yields than Szarvasi-1, which surprisingly best responds to organic fertilizer fertilization.
60

Techno-economic and life cycle analyses of lactic acid production from starch and lignocellulosic biofeedstocks

Manandhar, Ashish 18 June 2019 (has links)
No description available.

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