Spelling suggestions: "subject:"feeding."" "subject:"beeding.""
171 |
Studium vybraných faktorů na hospodářské vlastnosti silážní kukuřice / Study of selected factors influencing maize for silage agronomic attributesKADOUN, Lukáš January 2011 (has links)
In the years of 2009 and 2010, an observation of chosen quantitative and qualitative measures of several hybrids of corn took place at PS Humpolec and ZD Hosín. Quantitative measures were evaluated based on dissection of individual plants, qualitative measures then through common laboratory methods. In the field experiments at PS Humpolec, an observation of the seeding quantity and nitrogen load took place. The seeding quantity influenced with very high size of effect all agronomical and seed figures, except for the number of rows in the cob, where only high size of effect was observed. The quantity of 85 thousand seeds per hectare seems to be optimal. The nitrogen load influenced with very high size of effect the weight of the cob, with high size of effect the number of cobs and the weight of grains in the cob. Other measures were not affected. The year influenced with very high size of effect the length of the plant, the number of leaves, the weight of the cob; with high size of effect the height of the first cob on the plant and with considerable size of effect the number of cobs on the plant and the length of the cobs. Other observed measures were not affected by the year. Optimal nitrogen load that can be recommended is 110 kilograms per hectare. The best digestibility was noted with 100 thousand seeds per hectare and 110 Kg of nitrogen per hectare, or with 70 thousand seeds per hectare with no nitrogen. In the operational and half-operational experiments at ZD Hosín, differences between chosen hybrids were observed. Based on the results, the best one that can be recommended for these environmental conditions is Karacho, with FAO 260. Hybrid Karacho achieved the highest yield of matter in both years and in the year of 2010 it also achieved the best digestibility.
|
172 |
Analise espacial e multicriterial da qualidade das lavouras de milho "Safrinha" no medio Paranapema / Spatial ana lyze and multicriteria evaluation of agricultural quality off-season maize "Safrinha" in middle Paranapema river valley, SP, BrazilDias, Hugo de Souza 14 December 2006 (has links)
Orientador: Rubens A. C. Lamparelli / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-09T11:52:38Z (GMT). No. of bitstreams: 1
Dias_HugodeSouza_D.pdf: 5685544 bytes, checksum: 3cf72b0dbfd181c88c6ebe9be676447d (MD5)
Previous issue date: 2006 / Resumo: Apesar do milho "safrinha" já representar uma grande proporção do milho produzido no Brasil e ter tido um significativo aumento de produtividade nos últimos anos, esta cultura ainda é relacionada ao baixo uso de tecnologia e à baixa produtividade. A primeira etapa deste estudo analisa as estatísticas e as relações entre os seguintes itens de verificação da qualidade das lavouras: data de semeadura; cobertura morta do solo; espaçamento das entrelinhas; estande e população de plantas; plantas problema; espaços entreplantas; infestação de ervas daninhas e perdas de colheita. A segunda etapa analisou a correlação espacial destas variáveis entre os diferentes talhões amostrados e mapeou a sua distribuição através das ferramentas da geoestatística na região do Médio Paranapanema. Na terceira etapa as variáveis foram utilizadas como critérios em uma avaliação multicriterial gerando um mapa de qualidade das lavouras. O método de polígonos de Thiessen foi utilizado no desagrupamento das estatísticas básicas (média, variância, assimetria), minimizando os problemas originados pela não aleatoriedade espacial da amostragem. O sistema de Plantio Direto (PD) foi discriminado estatisticamente do sistema de Preparo Convencional (PC) através de diversas variáveis, mas apenas a cobertura morta discriminou o PD da Semeadura na Palha de Inverno (SPi) e do PC. Oitenta e cinco por cento dos talhões avaliados tinham estande dentro dos limites aceitáveis e boa distribuição de plantas. Sessenta por cento dos itens de verificação apresentaram continuidade espacial entre talhões, o que permitiu o mapeamento através de krigagem ordinária. As áreas não ocupadas com milho foram retiradas da análise espacial utilizando-se uma máscara do uso da terra produzida pela classificação de imagens de satélite. A análise multicriterial (MCE) combinou o processo de análise hierárquica (AHP), para dar pesos aos critérios, e conjuntos fuzzy, para normalizar os critérios, possibilitando a avaliação e o mapeamento da qualidade das lavouras de milho "safrinha" em uma área de 1.577 km2.
Palavras chaves: sistemas de preparo de solo; auditoria de qualidade; polígonos de Thiessen; sistemas de suporte a decisão; processo de análise hierárquica (AHP) / Abstract: Even though off-season or winter maize ("safrinha") today accounts for a large fraction of Brazilian maize production, and has displayed a significant increase in yield during the past few years, this crop is still associated with low technology and low yield. The first part of this study analyzes the statistics and relations among several variables of agricultural quality (items of quality verification): planting date; crop mulch cover; row spacing; plant stand and population; problem plants; plant spacing; weed infestation; harvest losses. The second part analyzes the spatial correlation of these variables among different plots sampled and maps the distribution by using spatial statistical tools in the Middle Paranapanema River Valley. In the third part, the variables were used as criteria in a multicriteria evaluation (MCE) that created an agricultural quality maps. Thiessen polygons were used to declustering the basic statistics (mean, variance, coefficient of skewness), minimizing problems introduced by non-random spatial sampling. No-tillage cultivation was statistically discriminated from conventional tillage by several variables, but only crop mulch cover separated no-tillage from winter crop mulch cultivation and conventional tillage. Eighty-five percent of plots studied had stands within acceptable limits and displayed good distribution of plants. Sixty percent of the variables showed spatial continuity among the plots, which permitted mapping by use ordinary kriging. Areas not planted in maize were removed from the spatial analysis using a mask of land use produced by a classification of satellite imagery. Multicriteria evaluation (MCE) combined the Analytic Hierarchy Process (AHP) to weight the criteria, and fuzzy sets were used to normalize the criteria, permitting the evaluation and mapping of agricultural quality of off-season ¿safrinha¿ maize in an area of 1,577 km2.
Index terms: tillage systems; quality audit; Thiessen polygons; decision making; analytic hierarchy process (AHP) / Doutorado / Planejamento e Desenvolvimento Rural Sustentável / Doutor em Engenharia Agrícola
|
173 |
Topologias WDM-PON utilizando auto-alimentação com dupla cavidade óptica para Fronthaul analógico de redes 5G / Double-cavity self-seeding WDM-PON topologies as 5G networks analog FronthaulAdelcio Marques de Souza 10 September 2018 (has links)
As futuras redes de acesso sem-fio, como a quinta geração de telefonia celular (5G), estão introduzindo e consolidando diversas tecnologias, tais como a operação em ondas milimétricas, picocélulas e o emprego massivo de antenas para diversidade espacial e temporal. Todas essas mudanças trazem desafios para a capacidade dos enlaces presentes nessas redes, como o backhaul e fronthaul. Nas últimas gerações, o ifronthaul tem utilizado Rádio-sobre-Fibra Digital (D-RoF, Digital Radio-over Fiber). Entretanto, neste novo paradigma, o processo de digitalização pode vir a consumir uma largura de banda excessiva e a transmissão analógica dos sinais de RF sobre a fibra se torna uma solução mais atrativa. Ao mesmo tempo, WDM-PON (Wavelength-Division-Multiplexing Passive-Optical-Network) é uma proeminente alternativa para o futuro das PONs, especialmente considerando o seu emprego como fronthaul. Para reduzir a necessidade de diversos transmissores diferentes, várias técnicas de auto-alimentação para obtenção de fontes ópticas agnósticas em comprimento de onda têm sido propostas. O presente trabalho faz um estudo de topologias de auto-alimentação com dupla cavidade para operarem como fronthaul analógico nas futuras redes de acesso sem-fio. Simulações numéricas utilizando o software Optisystem demonstram a viabilidade destas topologias em diversos cenários previstos para estas redes de acesso, especialmente considerando a operação em ondas milimétricas. Transmissões bem sucedidas foram obtidas para sinais ASK, M-PSK e M-QAM em frequências de microondas (1,25, 2,5 e 5 GHz) e ondas milimétricas (38 e 60 GHz) com vazões de 155 Mbps a 10 Gbps utilizando modulação direta e modulação externa. / Future radio access networks, such as the fifth generation mobile network (5G), are introducing and consolidating disruptive technologies, such as millimeter wave operation, dense picocell coverage and massive use of antennas for spatial and temporal diversity. These new technologies present a challenge for the capacity of the links that are present on these networks, including backhaul and fronthaul. In the latest cellular network generations, the fronthaul was typically implemented by Digital Radio-over-Fiber (D-RoF) technique. However, in this future context, the digitalization process would require a prohibitive bandwidth and the analog transmission of RF signals over the fiber can be a more attractive solution when compared to D-RoF. At the same time, Wavelength-Division-Multiplexing PON (WDM-PON) is prominent alternative for the future of PONs, especially considering its use as fronthaul. In order to avoid employing numerous distinct transmitters, several self-seeding techniques have been proposed to achieve colorless optical sources. This dissertation presents a numerical study of double-cavity self-seeding topologies to serve as analog fronthaul for future radio access networks. Numerical simulations using the software Optisystem demonstrate the feasibility of these topologies in various scenarios envisioned for these access networks, especially considering operation in millimeter waves. Successful transmission was achieved for ASK, M-PSK and M-QAM signals at microwave (1.25, 2.5 and 5 GHz) and millimeter wave (38 and 60 GHz) frequencies with throughput of 155 Mbps to 10 Gbps using direct and external modulation.
|
174 |
Efeito da inoculação com rizóbio no estabelecimento, crescimento inicial e abundância natural de 15N em leguminosas (Fabaceae) arbóreas nativas plantadas por semeadura direta / Effect of rhizobia inoculation on establishment, initial growth and 15N natural abundance in direct-seeded native legume (Fabaceae) treesPablo Guenther Soares 26 March 2007 (has links)
O presente estudo teve como objetivo avaliar o efeito da inoculação com rizóbio no estabelecimento, crescimento inicial e em alguns aspectos da dinâmica de N em folhas de leguminosas (Fabaceae) arbóreas nativas plantadas por semeadura direta no campo, em área de mata ciliar no Estado de São Paulo. Foi avaliada a emergência de plântulas (% em relação ao número de sementes plantadas) até os 3 meses após a semeadura (MAS) e o crescimento em altura aos 13 MAS. O fracionamento isotópico do N foliar também foi avaliado, pelo método da abundância natural do 15N, além da concentração de N e a razão C/N foliar. Acacia polyphylla foi usada como planta-referência não-fixadora de N2. Em relação ao desenvolvimento inicial, houve grande variação entre as espécies estudadas. Acacia polyphylla e Enterolobium contortisiliquum apresentaram taxa de germinação mediana e rápido crescimento. Mimosa bimucronata e Parapiptadenia rigida tiveram crescimento relativamente rápido, porém baixo potencial germinativo. Erythrina speciosa e Poecilanthe parviflora, com crescimento lento, apresentaram germinação elevada no campo. As espécies fixadoras de N2 mostraram δ15 N médio de 2,7‰, enquanto que a referência Acacia polyphylla se mostrou cerca de 4,0‰ mais enriquecida em 15N . Erythrina speciosa e Ormosia arborea apresentaram os menores valores de δ15N, enquanto que Parapiptadenia rigida, enriquecida em 15N, mostrou estar obtendo N exclusivamente do solo. Poecilanthe parviflora, Mimosa bimucronata e Enterolobium contortisiliquum apresentaram valores intermediários de δ15N, com grande variação entre os indivíduos amostrados. A concentração de N nos tecidos foliares variou entre 1,5% e 3,6%. De forma geral, esta variável não mostrou relação direta com o δ15N das plantas. A menor razão C/N foi observada em Enterolobium contortisiliquum e Erythrina speciosa, seguida por M. bimucronata. Nas condições experimentais locais, as plantas não responderam à inoculação com rizóbio em nenhum dos parâmetros avaliados (estabelecimento, crescimento inicial, δ15N, concentração de N e razão C/N). As espécies de crescimento mais lento e com alta incidência de herbivoria observados no campo (E. speciosa e O. arborea) foram também as que apresentaram δ15N na faixa considerada como de ocorrência da fixação biológica de nitrogênio. Os resultados indicam, para as outras espécies, maior aquisição de N proveniente do solo. / The aim of this work was to assess the effect of rhizobia inoculation on the establishment, early growth and some aspects of N dynamics in direct-seeded native legume (Fabaceae) trees in a riparian zone of São Paulo State, Southeastern Brazil. Seedling emergency (% of total planted seeds) was evaluated until three months after sowing (MAS), and the height of the trees were measured at 13 MAS. Isotopic N fractionation was also assessed by the 15N natural abundance method, as well as foliar N content and C/N ratio. Acacia polyphylla was used as a non-N2-fixing reference plant. Acacia polyphylla and Enterolobium contortisiliquum grew most rapidly, with moderate germination rate. Mimosa bimucronata and Parapiptadenia rigida were fast-growing but with low establishment rate. Erythrina speciosa and Poecilanthe parviflora showed low growing rate, but high germination potential. The N2-fixers showed an average foliar δ15N of 2,7‰, while the reference-plant was 4,0‰ more <sup15>N enriched. Erythrina speciosa and Ormosia arborea showed the lowest δ15N values. The high δ15N of Parapiptadenia rigida probably indicated that it is obtaining N exclusively from the soil. Poecilanthe parviflora, Mimosa bimucronata and Enterolobium contortisiliquum showed intermediate δ15N values, with strong variations among the sampled individuals. Foliar N concentrations varied from 1,5% to 3,6%. In general, N concentrations were not correlated with foliar δ15N . The lowest C/N ratio was observed on E. contortisiliquum and E. speciosa , followed by M. bimucronata. In this field trial conditions, rhizobia inoculation did not show differences in all surveyed parameters (establishment, early growth, foliar δ15N, total N content and C/N ratio of trees). The slow-growing species, E. speciosa and O. arborea , that also had a high herbivore attack observed in the field, showed foliar δ15N in the biological N2 fixation range. The results suggested, for the other species, a larger soil N acquisition.
|
175 |
Modelo para estimação da produtividade de grãos de milho no estado de São Paulo. / Model to estimate corn yield at São Paulo state, Brazil.Luis Gonzaga Medeiros de Figueredo Júnior 26 March 2004 (has links)
O presente trabalho tem por objetivo propor um modelo para estimação da produtividade de grãos de milho para o Estado de São Paulo com base nos valores mensais de temperatura, radiação solar e chuva, no intuito de disponibilizar ferramenta para o planejamento regional (identificação das épocas do ano e dos locais mais indicados para o cultivo de milho). O uso de modelos de crescimento e desenvolvimento vegetal possibilita uma economia de tempo, trabalho e quantidade de recursos para tomada de decisões referentes ao manejo no setor agrícola por possibilitar uma previsão do processo de interesse e/ou um melhor entendimento do sistema em estudo. O conhecimento da quantidade de energia solar disponível às plantas, bem como da capacidade de conversão da mesma em energia química metabólica, possibilita prever produtividade de grãos, no caso do milho, quanto à eficiência de conversão em biomassa, através de um modelo geral mecanístico, levando em consideração aspectos agrometeorológicos, fisiológicos, genéticos e edáficos. A assimilação de CO2 pode ser convertida em massa de carboidrato, produzida durante o processo de fotossíntese, em função do índice de área foliar, temperatura e radiação solar absorvida. Estimando-se os valores de radiação solar absorvida, fotoperíodo, índice de área foliar e duração do ciclo, considerando as correções quanto à respiração de manutenção e crescimento, bem como a variação temporal da área foliar, pode-se transformar esse valor em massa líquida de carboidrato total final produzida durante o ciclo. O balanço hídrico foi utilizado com a finalidade de estimar a deficiência hídrica durante o ciclo da cultura de milho, sendo adotado o método de Thornthwaite & Mather (1955), sendo a evapotranspiração de referência estimada pelo método de Thornthwaite (1948). A produtividade deplecionada de grãos de milho foi estimada a partir dos dados de produtividade potencial predita pelo modelo, considerando-se a depleção em função da evapotranspiração relativa (relação entre evapotranspiração real e evapotranspiração da cultura). A partir de dados climáticos obtidos de estações e postos meteorológicos localizados em diversas partes do estado de São Paulo, foram elaborados mapas de superfície no programa TNTmips, com a identificação, por município, das localidades com potencial para o desenvolvimento da cultura de milho. Através destes mapas, é possível identificar restrições quanto à deficiência hídrica, temperatura, radiação solar, produtividade potencial e produtividade de grãos de milho no estado de São Paulo. / The present work has the objective to suggest a model to estimate potential yield and corn yield for São Paulo state based on monthly values of temperature, solar radiation and rainfall, in order to dispose a tool for regional planning (identification of sites and timing during the year more indicated for maize cropping). The use of growing and development models allows savings in time, work and resources needed for making decisions regarding agricultural management, by enabling a preview of the process of interest and/or a better understanding of the system being studied. The knowledge of the available amount of solar energy to plants and the capability of those to convert it into metabolic chemical energy, allows to preview grain yield, in the case of corn, regarding to biomass converting efficiency, through a general mechanistic model, considering agro-meteorological, physiological, genetical and edaphological aspects. The carbon dioxide (CO2) assimilation can be converted into mass of carbohydrates produced during photosynthesis process, as a function of leaf area index, air temperature and absorbed solar radiation. By estimating the values of solar radiation, the photoperiod, the leaf area index, and the cycle length, and considering the corrections related to growing and maintenance respiration, as well as the temporal variation of leaf area, it is possible to transform those value into final net mass of total carbohydrate produced during the cycle. The hydric balance, as proposed by Thornthwaite & Mather (1955), was used with the objective to estimate the hydric deficit during maize cycle, being the reference evapotranspiration being estimated by Thornthwaite (1948). Corn yield was estimated up from potential yield predicted by the model, considering the depletion from the relative evapotranspiration (relation between real evapotranspiration and crop evapotranspiration). Starting from climatic data obtained from several meteorological station located at different sites in São Paulo State, Brazil, surface maps were elaborated using TNTmips software, with the identification, by county, of those sites with maize development potential. Through those maps it is possible to identify restriction regarding hydric deficit, temperature, solar radiation, potential yield, and corn yield in São Paulo State.
|
176 |
Comportamento da plasticidade de plantas de soja frente a falhas e duplas dentro de uma população / Behavioral plasticity of soybean plants against faults and double within a populationPinto, Jonas Farias 17 October 2010 (has links)
Made available in DSpace on 2014-08-20T13:44:50Z (GMT). No. of bitstreams: 1
dissertacao_jonas_pinto.pdf: 226264 bytes, checksum: f4890ee9608918a926a9fc2d8ccb6362 (MD5)
Previous issue date: 2010-10-17 / The seeder are designed to provide an even distribution of seeds in the field.
Equipment failure, bad standardizing seeds and use of low quality seed to favor the
emergence of faults and double plants in a crop. This study aimed to evaluate the
behavior and the effects of faults and double plants on soybean productivity. Have
been sown soybean seeds, variety CD 226 RR. Spacing of 6,5cm between plants
and 50cm between rows were used. Sowing was done manually using three seeds
per hole, ten days after the onset of the emergency were performed thinning leaving
one plant per hole, two plants per hole (twin plants) and the occurrence of failures
that made up the treatment plant as follows: PIN - Normal Individual Plan; PII -
Isolated Single Plant, PIF 13 - Individual Plant located on the edge of failure 13cm;
PIF 26 - Individual Plant located on the edge of failure 26cm; PIF 39 - Individual Plant
located on the edge of failure 39cm; PIF 45,5 - Single Plant located on the edge of
failure 45,5cm; NDP - Plant Normal Double; PDI - Dual Isolated Plant, PDF 13 -
Double Plant located on the edge of failure 13cm, PDF 26 - Double Plant located on
the edge of failure 26cm ; PDF 39 - Double Plant located at the edge of failure 39cm;
PDF 45,5 - Double Plant located on the edge of failure 45,5cm. In the developmental
stage R8 was evaluated in the field the following characteristics: plant height (cm),
number of branches per plant and stem diameter (mm). In the laboratory we
determined the number of pods per plant, number of seeds per plant, seed weight
per plant (g) and productivity per unit area (kg.ha-1). Based on the results we
obtained the following conclusions: failures from 1 up to 7 consecutive plants per
linear meter cause reductions of 6 up to 38% in productivity; Increased production
plant located on the edges of fault does not offset the loss of production caused the
lack of plants; the occurrence of until one double plant per meter does not decrease
productivity. / As semeadoras foram desenvolvidas para propiciar uma distribuição
homogênea das sementes no campo. Falhas no equipamento, sementes mal
padronizadas e utilização de sementes de baixa qualidade favorecem para o
surgimento de falhas e de plantas duplas em uma lavoura. O presente trabalho teve
por objetivo avaliar o comportamento e os efeitos de falhas e duplos na
produtividade da soja. Foram semeadas sementes de soja, cultivar CD 226 RR.
Utilizou-se o espaçamento de 6,5cm entre plantas e 50cm entre linhas. A semeadura
foi realizada manualmente utilizando-se 3 sementes por cova, dez dias após o início
da emergência foram realizados desbastes deixando uma planta por cova, duas
plantas por cova (plantas duplas) e a ocorrência de falhas de plantas que
compuseram os tratamentos da seguinte forma: PIN - Planta Individual Normal; PII -
Planta Individual Isolada; PIF 13 - Planta Individual localizada em borda de Falha
13cm; PIF 26 - Planta Individual localizada em borda de Falha 26cm; PIF 39 - Planta
Individual localizada em borda de Falha 39cm; PIF 45,5 - Planta Individual localizada
em borda de Falha 45,5cm; PDN - Planta Dupla Normal; PDI - Planta Dupla Isolada;
PDF 13 - Planta Dupla localizada em borda de Falha 13cm, PDF 26 - Planta Dupla
localizada em borda de Falha 26cm; PDF 39 - Planta Dupla localizada em borda de
Falha 39cm; PDF 45,5 - Planta Dupla localizada em borda de Falha 45,5cm. No
estádio fenológico R8 foram avaliadas as seguintes característica no campo: altura
de plantas (cm), número de ramificações por planta, diâmetro do caule (mm). Em
laboratório determinou-se o número de legumes por planta, número de sementes por
planta, peso das sementes por planta (g) e produtividade por unidade de área
(kg.ha-1). Com base nos resultados, obtiveram-se as seguintes conclusões: falhas de
1 a 7 plantas consecutivas por metro linear causam reduções na produtividade de 6
a 38%; o aumento da produção das plantas localizadas nas bordas das falhas não
compensa a perda de produção causada pela falta de plantas; a ocorrência de até
uma planta dupla por metro linear não diminui a produtividade.
|
177 |
La nucléation à partir de cristaux mixtes : une nouvelle approche pour augmenter la diversité polymorphiqueLévesque, Alexandre 01 1900 (has links)
Les composés qui existent sous de multiples formes cristallines sont qualifiés de polymorphiques. Les polymorphes ont la même composition, mais leurs structures et leurs propriétés peuvent varier significativement. Dans de nombreux domaines, les conditions de cristallisation des composés d’intérêt sont étudiées de façon exhaustive afin de générer autant de polymorphes que possible, à partir desquels le polymorphe le plus avantageux pour l’application souhaitée peut être sélectionné. Nous rapportons une nouvelle façon d’augmenter la diversité polymorphique basée sur la cristallisation induite par l’ensemencement à l’aide de cristaux mixtes. Nous rapportons également une nouvelle stratégie de cristallisation de composés fondus suspendus qui permet d’induire la formation de cristaux uniques qui sont trop instables pour être produits par des méthodes traditionnelles. Cette stratégie permet la résolution par diffraction des rayons X d’une plus large variété de structures cristallines. L’efficacité des méthodes présentées ci-dessus a été démontrée en les utilisant pour produire des cristaux uniques caractérisés par diffraction des rayons X de nouveaux polymorphes du composé ROY, une référence en matière de polymorphisme. Cela permet à ROY de regagner sa part de la position de composé le plus polymorphique dans la Cambridge Structural Database (CSD). / Chemical compounds that exist in multiple crystalline forms are said to exhibit polymorphism. Polymorphs have the same composition, but their structures and properties can vary markedly. In many fields, conditions for crystallizing compounds of interest are screened exhaustively to generate as many polymorphs as possible, from which the most advantageous form for the desired application can be selected. Here we report a new way to increase polymorphic diversity, based on crystallization induced by suitably designed mixed-crystal seeds. Also reported herein is a new strategy of suspended-melt crystallization, which can be used to induce the formation of single crystals that are too unstable to be produced by traditional methods. This strategy allows for a broader scope of crystalline structures to be resolved by X-ray diffraction. The efficacy of the above methods has been demonstrated by using them to produce new polymorphs of the benchmark compound ROY as single crystals structurally characterized by X-ray diffraction. This allows ROY to reclaim a share of the crown as the most polymorphic compound in the Cambridge Structural Database (CSD).
|
178 |
Novel Techniques to Improve Restoration of Native Rangeland SpeciesAnderson, Rhett Michael 27 March 2020 (has links)
The sagebrush steppe is a particularly sensitive ecosystem that is easily disturbed by fires, oil and gas extraction, woody-plant encroachment, and overgrazing. The natural regeneration of native species following a disturbance within this system is typically slow and sporadic, which allows invasive grasses to occupy the landscape. Attempts to assist the recovery of these landscapes through direct seeding is commonly met with poor success rates, particularly in lower elevation, drier sites. Novel seed enhancement technologies and planting techniques that mitigate limiting factors impairing restoration efforts may improve the likelihood of restoring these degraded areas. For chapter 1, we evaluated a solid-matrix priming technique, where bluebunch wheatgrass (Pseudoroegneria spicata) and Lewis flax (Linum lewisii) were primed and then the priming matrix and seed were pelleted together. We evaluated primed seed that had been incorporated into pellets at two field sites against seed that was pelleted but been left unprimed, and untreated seed (control). These three seed treatments were planted in the spring (mid-march) in shallow (2-cm) and deep (15-cm) furrows, in a complete factorial design. We found that primed seeds generally produced higher plant densities than control seed at the beginning of the growing season; however, its influence diminished towards the end of the growing season. We also found that deep furrows increased plant density throughout the growing season and even into the following year. The combination of priming and deep furrows outperformed control seed in shallow furrows in all measured metrics. For chapter 2, we evaluated a seed conglomeration technique for improving Wyoming big sagebrush (Artemisia tridentata ssp. Wyomingensis) emergence and survival under fall and winter plantings. The trial was implemented at five sites across Utah and Nevada in a randomized complete block-split-split plot design, with site, and planting season, comprising the split-plot factors. Each site and season combination was seeded with conglomerated and control seed. We found that in most cases, a fall seeding of Wyoming big sagebrush was either the same or more successful compared to planting on the snow in the winter, which is the current suggested practice. Our results also demonstrated that seed conglomeration produced higher plant densities compared to control seed throughout the growing season. The higher density of plants produced from conglomerates combined with the improved seed delivery provided by the conglomeration technique was estimated to offset the cost in producing conglomerates and reduce overall restoration costs by 41%.
|
179 |
Particle image velocimetry measurements of blood flow in aneurysms using 3D printed flow phantomsTshimanga, Ilunga Jeanmark 11 1900 (has links)
Cardiovascular diseases (CVD) remain one of the leading causes of deaths worldwide. The formation and
presence of aneurysm is a very important question in the study of this CVDs. An aneurysm is a balloon-like
bulge on a blood vessel which forms over time. An aneurysm is usually considered to be a result of weakening
of the blood vessel walls, this definition has stood over many years without being conclusively proven.
Eventually, the aneurysm could clot or burst due to degradation of the aneurysm wall and accumulation of
blood. The latter would lead to internal bleeding and result in a stroke. Local hemodynamics have been found
to be very important in the study of the evolution of an aneurysm. In this study, a steady flow experimental
investigation was conducted using planar Particle Image Velocimetery (PIV) on a rigid flow phantom of an
idealised geometry consisting of a curve parent artery and a spherical aneurysm located on the outer convex
side of the curvature. The flow phantom was fabricated directly using a commercially available desktop
Stereolithography (STL) 3D printer instead of the more conventional investment casting method using a core.
Although 3D printing technologies have been around for many years, the fabrication of flow phantoms by
direct printing is still largely under-explored. This thesis details the results of investigation into the optimal
printing and post-printing procedures required to produce a flow phantom of suitable clarity and transparency.
Other important areas of concern such as the geometric accuracy, surface topography and refractive index of
the final model are also investigated. A planar PIV is conducted to study the impact of flow rates on the local
flow field in and around the aneurysm and their impact on the wall shear stress. It was found that direct 3D
printing is appropriate for the fabrication of flow phantoms suitable for PIV or other flow visualisation
techniques. It reduces the complexities and time needed compared to the conventional investment casting
methods. It was observed that the optical properties of the printed material such as the high refractive index
(RI) and the transmittivity of light could cause a problem in large models. From the PIV measurements it was
found that flow rates affect the flow field in both the parent artery and the aneurysm. First, high velocities
were observed on the outer curvature of the parent artery. Secondly the centre of rotation in the aneurysm is
not at the geometric centre but is displaced slightly in the direction of the flow. Finally, the flow rate affects
the angle in which flow enters the aneurysm from the parent vessel. This change in the flow angle affects the
flow within the aneurysm. A higher flow rate in the parent artery increases the incident angle which brings the
centre of rotation closer to the geometric centre of the aneurysm, this changes the location and magnitude of
high velocities and hence the local wall shear stress (WSS) on the wall of the aneurysm. This may have
implications in the evolution of aneurysms. / Mechanical and Industrial Engineering
|
180 |
Effects of Soybean Seeding Rate on Plant-to-Plant Variability, Yield, and Soybean Cyst NematodeMoore, Jenna Marie 04 October 2021 (has links)
No description available.
|
Page generated in 0.3029 seconds