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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.
21

Alterações microbiológicas e químicas na silagem de cana-de-açúcar (Saccharum officinarum L.) in natura e queimada, inoculadas ou não, com Lactobacillus buchneri /

Vittori, Juliano. January 2009 (has links)
Orientador: Ruben Pablo Schocken-Iturrino / Banca: Hélio José Montassier / Banca: Alessandra Aparecida Medeiros / Resumo: Visando suplementar ruminantes no período seco, a cana-de-açúcar nos últimos anos tem sido bastante pesquisada e empregada como volumoso alternativo, principalmente na forma de silagem. Na ensilagem desta forrageira, principalmente quando utilizada após queima do canavial, ocorre uma alta atividade de leveduras epífitas que convertem os carboidratos solúveis da forragem em etanol, gás carbônico e água, levando a elevadas perdas de matéria seca, aumento no teor de fibra em detergente neutro e diminuição de consumo. Buscando amenizar esses problemas temse pesquisado inoculantes bacterianos compostos por bactérias ácido-produtoras, tais como o Lactobacillus buchneri. Sendo assim, objetivando avaliar os efeitos antimicrobianos e químicos na silagem de cana-de-açúcar queimada e inoculada com Lactobacillus buchneri, quatro silos de superfície foram analisados por meio dos seguintes tratamentos: cana-de-açúcar crua sem aditivo; cana-de-açúcar crua inoculada com L. buchneri; cana-de-açúcar queimada sem aditivo e cana-de-açúcar queimada e inoculada com L. buchneri. As amostragens foram efetuadas após 0, 21, 49, 77 e 105 dias de utilização dos silos, sendo retiradas do centro e superfície do painel. Houve redução na população de leveduras e fungos filamentosos nas silagens inoculadas e aumento nas queimadas. Constatou-se maior população de microrganismos na camada superficial, além de maiores valores de pH e nitrogênio amoniacal. Ocorreram menores perdas de matéria seca na silagem de cana-de-açúcar queimada e inoculada em relação ao seu controle. As silagens apresentaram os fungos filamentosos Aspergillus, Penicillium, Trichoderma, Rhizopus e Neurospora após abertura, verificando-se redução na frequência dos mesmos ao longo do período. O inoculante exerceu um efeito redutor na população de leveduras e na perda de MS sendo esse efeito potencializado pela... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In order to supplement ruminants's diets in dry period, sugarcane in the last years has been researched and processed as silage to used as an alternative food. In this ensilage process, mainly after sugar cane plantation have been set on fire, occurs a high activity of yeasts that convert the soluble carbohydrates of the forage in ethanol, carbon dioxide and water, leading to dry matter losses, increase in fiber content and decrease in the intake. In a way to solve those problems bacterial inoculants produced with acid-producers bacteria's, such as Lactobacillus buchneri, have been researched. Considering this the aim of the present study was to evaluate the microbiological and chemical effects on burned sugarcane silage when inoculated with Lactobacillus buchneri. Four silos type surface were analyzed using the following treatments: sugarcane without additives; sugarcane inoculated with L. buchneri; burned sugarcane without additives; and burned sugarcane inoculated with L. buchneri. The samples were taken after 0, 21, 49, 77 and 105 days after opening the silos and they were taken from the center and the surface of the panel. There was a reduction in the population of yeasts and filamentous fungi in inoculated silages and an increase of them in burned silages. There was a greater population of microorganisms in the superficial layer, in addition to higher pH values and ammoniacal nitrogen. The burned silage inoculated with L. buchneri showed the least amount of losses of dry matter in comparison to the control sample. The fungi Aspergillus, Penicillium, Trichoderma, Rhizopus and Neospora were found in the silages after opening the silos and the frequency of these microorganisms decreased with the passing of time. The inoculating had an reduccing effect in the yeast's population and in the loss of DM, and this effect was enhanced by the burn of the sugarcane... (Complete abstract click electronic access below) / Mestre
22

Bactérias diazotróficas endofíticas em cana-de-açúcar : estratégia para uma agricultura sustentável / Bacteria diazotrophic endophytic in sugar cane : strategy for sustainable agriculture

ANTUNES, Jadson Emanuel Lopes 25 February 2016 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-06-20T14:31:36Z No. of bitstreams: 1 Jadson Emanuel Lopes Antunes.pdf: 4190549 bytes, checksum: 65a41f6f1280ec224c9cb3bd749b7230 (MD5) / Made available in DSpace on 2016-06-20T14:31:36Z (GMT). No. of bitstreams: 1 Jadson Emanuel Lopes Antunes.pdf: 4190549 bytes, checksum: 65a41f6f1280ec224c9cb3bd749b7230 (MD5) Previous issue date: 2016-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Some Brazilian states, especially the Northeast, has its economy based on the cultivation of sugarcane, which depends on the success of this activity for the subsequent performance of its economy. In this context, priority is performing prospecting work diazotrophs and research to evaluate the potential of biological nitrogen fixation (BNF) in sugarcane under regional condition, applying technologies that enable the sustainable production of this crop. With that aimed to isolate and make characterizations morphophysiological, biochemistry and molecular endophytic bacteria stems and leaves of three varieties of sugarcane (RB1011, RB92579 and RB867515) and to evaluate the response of the cane sugar and the potential of BNF, the efficiency of inoculation of these bacteria as the productivity of stalks and technological qualities of sugarcane in the cycles of plant cane, cane ratoon and cane ressoca as support for sustainable crop production. 56 isolates were endophytic, being 62.5% and 37.5% of the stem of the leaf. We used molecular BOX-PCR technique that allows to differentiate into isolated sections 34 bands, for the formation of five distinct clusters that were selected for biochemical and / or physiological tests. These isolates, 66% were able to solubilize inorganic phosphate; 26% to produce urease, proteases produce 34%; 17% amylase to produce; 68% to produce lipase; 14% to produce chitinase; 17% of producing siderophore; 71% of produce ACC deaminase; 54% to produce N-acyl homoserine lactone (AHL); 51% to produce catalase and 23% showed hydrolytic ability to degrade gelatin; 97% reduced acetylene (ARA) with values between 4.14 and 7.84 nmol C2H4 / hour. To sequence the 16S rRNA ribosomal the presence of seven different genres, 46% identity was observed with the genus Bacillus, 20% to Paenibacillus, 14% Burkholderia, 6% Herbaspirillum, Pseudomonas and Methylobacterium and 3% Brevibacillus . Biochemical and molecular characterization of endophytic isolates stem and leaf of sugarcane revealed a diversity of bacteria colonizing this plant, with biotechnological potential to be used as biofertilizers. Three isolated by the nitrogenase activity and together with the responses of biochemical tests were selected to compose the microbial inoculant that was tested in the field for three years comprising the cycles of sugar cane plant, soca and ressoca the variety of sugarcane RB 92579 . We used the experimental randomized block design in a factorial 10x3, consisting of ten treatments (IPACC9 (Herbaspirillum seropedicae), IPA-CC33 (Pseudomonas sp.), IPA-CF65 (Bacillus Megaterium), IPA-CC9 + IPA-CC33, IPA-CC9 + IPA-CF65, IPA-CC33 + IPA-CF65, IPACC9 + IPA-CC33 + IPA-CF65, mix Embrapa (BR1140 (Azospirillum amazonense) BR11175 (H. seropedicae) BR11192 ( H. rubrisubalbicans) BR11284 (Gluconacetobacter diazotrophicus) and BR11364 (Burkholderia tropica), nitrogen witness (TN) and absolute control (TA)), three crop cycles (plant cane, cane and ratoon cane ressoca) with four replications totaling 40 plots for cultivation were evaluated the following parameters:.plant height, stem diameter, shoot dry weight, total nitrogen leaves +3, fresh stalk yield, sugar yield per hectare (TPH) content solids (° Brix) soluble fiber, total recoverable sugar (ATR) and estimation of the contribution of BNF nutrition of sugarcane by the technique of natural abundance of 15N isotope. Inoculation promoted significant gains compared to TA for the inoculated treatments was up to 57.31%. It found increases in productivity fresh stalk of up to 14 Mg ha-1 compared to TN, but not statistically differing from the other treatments. The similar behavior of the treatments inoculated with TN who received 60 kg ha-1 N, infers in low economic and environmental cost, and gains importance by the need to develop more sustainable agricultural practices to improve the quality of life of the population. / Alguns estados brasileiros, especialmente da região Nordeste, têm sua economia baseada na cultura da cana-de-açúcar, que depende do êxito dessa atividade para o consequente desempenho de sua economia. Nesse contexto, é prioritário realizar trabalhos de prospecção de bactérias diazotróficas e de pesquisas que avaliem a potencialidade da fixação biológica do nitrogênio (FBN) na cana-de-açúcar, sob condição regional, aplicando tecnologias que permitam a produção sustentável desta cultura. Com isso, objetivou-se isolar e efetuar caracterizações morfofisiológica, bioquímica e molecular de bactérias diazotróficas endofíticas de colmos e folhas de três cultivares de cana-de-açúcar (RB1011, RB92579 e RB867515), assim como avaliar a resposta da cana-de-açúcar quanto ao potencial de FBN, a eficiência da inoculação destas bactérias quanto à produtividade de colmos e qualidades tecnológicas de cana-de-açúcar nos ciclos da cana-planta, cana-soca e cana-ressoca como suporte a uma produção sustentável da cultura. Foram obtidos 56 isolados endofíticos, sendo 62,5% do colmo e 37,5% da folha. Utilizou-se a técnica molecular de BOX-PCR que permitiu diferenciar os isolados em 34 perfis de bandas, pela formação de cinco agrupamentos distintos, que foram selecionadas para os testes bioquímicos e/ou fisiológicos. Desses isolados, 66 % apresentaram capacidade de solubilizar fosfato inorgânico; 26 % de produzirem urease, 34 % de produzirem proteases; 17 % de produzirem amilase; 68 % de produzirem lipase; 14 % de produzirem quitinase; 17 % de produzirem sideróforo; 71 % de produzirem ACC deaminase; 54 % de produzirem N-acil-homoserina lactona (AHL); 51 % de produzirem catalase e 23 % apresentaram capacidade hidrolitica de degradarem a gelatina; 97 % reduziram acetileno (ARA) com valores entre 4,14 e 7,84 nmol C2H4/hora. Para o sequenciamento do gene 16S rRNA ribosomal, foi verificado a presença de sete diferentes gêneros, 46% de identidade com o gênero Bacillus , 20% com Paenibacillus, 14% com Burkholderia, 6 % com Herbaspirillum, Pseudomonas e Methylobacterium e 3% com Brevibacillus. A caracterização bioquímica e molecular dos isolados endofíticos de colmo e folha de cana-de-açúcar revelou uma diversidade de bactérias colonizando esta planta, com potencial biotecnológico para serem usadas como biofertilizantes. Foram selecionados três isolados pela atividade da nitrogenase e em conjunto com as respostas dos testes bioquímicos para compor o inoculante microbiano que foi avaliado em campo durante três anos compreendendo os ciclos da cana planta, soca e ressoca na variedade de cana-de-açúcar RB 92579. Utilizou-se o delineamento experimental em blocos casualizados, em esquema fatorial 10x3, constituído de dez tratamentos (IPA-CC9 (Herbaspirillum seropedicae), IPACC33(Pseudomonas sp.), IPA-CF65 (Bacillus Megaterium), IPA-CC9 + IPA-CC33, IPACC9 + IPA-CF65, IPA-CC33 + IPA-CF65, IPA-CC9 + IPA-CC33 + IPA-CF65, Mistura Embrapa (BR1140 (Azospirillum amazonense), BR11175 (H. seropedicae), BR11192 (H. rubrisubalbicans), BR11284 (Gluconacetobacter diazotrophicus) e BR11364 (Burkholderia tropica), testemunha nitrogenada (TN) e testemunha absoluta ( TA)), três ciclos de cultivo (cana-planta, cana-soca e cana-ressoca) com quatro repetições, totalizando 40 parcelas por cultivo. Foram avaliados os seguintes parâmetros: altura de plantas, diâmetro do colmo, massa seca da parte aérea, nitrogênio total das folhas +3, produtividade do colmo fresco, rendimento de açúcar por hectare (TPH), teor de sólidos solúveis totais (°Brix), fibra, açúcar total recuperável (ATR) e estimativa da contribuição da FBN na nutrição da cana-de-açúcar pela técnica de abundância natural do isótopo 15N. A inoculação promoveu ganhos significativos em comparação a TA para o diâmetro do colmo e ATR, para o cultivo canaressoca. A contribuição da FBN nos tratamentos inoculados foi de até 57,31%. Constatou-se incrementos na produtividade do colmo fresco de até 14 Mg.ha-1 em comparação a TN, porém não diferenciando estatisticamente dos outros tratamentos. O comportamento semelhante dos tratamentos inoculados com a TN que recebeu 60 kg.ha‑1 de N, infere em baixo custo econômico e ecológico, e ganha importância pela necessidade para o desenvolvimento de práticas agrícolas mais sustentáveis para melhorar a qualidade de vida da população.
23

Avaliação de cultivares de feijão-caupi quanto à eficiência para fixação biológica de nitrogênio com estirpes isoladas de solos do semiárido de Pernambuco / Evaluation of cowpea cultivars for biological nitrogen fixatio with strains isolated from Pernambuco semiarid soils

ARRUDA, Aline Medeiros de 18 February 2016 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-09-19T13:21:55Z No. of bitstreams: 1 Aline Medeiros de Arruda.pdf: 1077427 bytes, checksum: edf33aaa98a044c16135de656116b3d2 (MD5) / Made available in DSpace on 2016-09-19T13:21:55Z (GMT). No. of bitstreams: 1 Aline Medeiros de Arruda.pdf: 1077427 bytes, checksum: edf33aaa98a044c16135de656116b3d2 (MD5) Previous issue date: 2016-02-18 / Due to it adaptability and nutritive value, cowpea (Vigna unguiculata) is an important protein source in some regions of Brazil, with good perspectives in the Brazilian agribusiness. This pulse, in symbiosis with nitrogen fixing bacteria, has a high nitrogen fixation potential, and may dispense completely or partially nitrogen fertilizers, reducing production costs. The evaluation of native populations of these bacteria in cowpea cultivars allows the selection of efficient strains, adapted to local conditions, and leading to higher cowpea yields. This work aims to evaluate the symbiotic efficiency of rhizobial populations from Pernambuco State semiarid soils as a more efficient method for the selection of rhizobial strains for inoculant production, using three cultivars of cowpea (BRS Marataoã, BRS Guariba and IPA 206). Soil samples were collected from the 0-0.1 m depth layer in different Pernambuco municipalities from two groups of soil, one high and one low fertility. An experiment was done to collect nodules for isolation, and isolates were morphologically characterized in YMA media. Shannon-Weaver’s diversity, Simpson’s dominance, Margalef’s richness and Pielou’s uniformity indexes were calculated for each soil group. Rhizobial populations were evaluated in Leonard jars in a greenhouse. Shoot (MSPA), root (MSR) and nodules (MSN) dry masses, nodule number (NN), shoot nitrogen accumulation (ANPA) and relative efficiency (ER) were determined and submitted to analysis of variance and means comparison by the Scott-Knott test at 5% probability. Most of the more efficient isolates were from the low fertility soil, in special isolate 49. The lower diversity from the high fertility soils may be due to a reduced dependence of the legumes on biological nitrogen fixation, while the higher dependency of lower fertility soils may have applied a selective pressure towards more efficient strains. BRS Guariba had higher ER, showing good symbiotic specifity with the strains. / Devido às condições de adaptabilidade e valor nutritivo, o feijão-caupi (Vigna unguiculata) tornou-se importante fonte de proteína em algumas regiões do país, permitindo ampla perspectiva no agronegócio brasileiro. Esta leguminosa granífera possui alta capacidade de fixar N em simbiose com bactérias fixadoras de nitrogênio, da qual podem dispensar total ou parcialmente os fertilizantes nitrogenados, o que reduz os custos de produção, além de servir como alicerce ao programa de melhoramento vegetal. A avaliação de populações nativas destas bactérias em cultivares de feijão-caupi permite a seleção de estirpes eficientes, adaptados às condições locais, resultando no aumento de produtividade do feijão-caupi. Este trabalho tem como objetivo avaliar a eficiência simbiótica de populações rizobianas, provenientes de solos do semiárido pernambucano (Brazil), como método mais eficiente para seleção de estirpes rizobianas para recomendação para produção de inoculantes em três variedades de feijão-caupi: BRS Marataoã, BRS Guariba e IPA 206. Amostras de solos foram coletadas na camada de 0-0,1m de profundidade em diferentes municípios pernambucanos, provenientes de dois grupos de solos, um com alta fertilidade e outro de baixa fertilidade. Um experimento foi conduzido para a obtenção de nódulos para isolamento e os isolados foram caracterizados morfologicamente em meio YMA. Os índices de diversidade de Shannon-Weaver, dominância de Simpson, riqueza de Margalef e uniformidade de Pielou, foram calculados para cada grupo de solo. As populações de rizóbios foram avaliadas em vasos de Leonard em casa de vegetação utilizando o delineamento experimental de blocos casualizados com quatro repetições. As necessidades nutricionais do feijão-caupi foram supridas com solução nutritiva. Foram observadas e avaliadas as seguintes variáveis: Massa seca da parte aérea (MSPA) e raiz (MSR), número (NN) e massa de nódulos secos (MSN), acúmulo de nitrogênio na parte aérea (ANPA) e eficiência relativa (ER). Estas variáveis foram submetidas à análise de variância com as médias comparadas pelo teste de Skott Knott a 5% de probabilidade, utilizando-se o programa estatístico SISVAR 5.3. A maioria dos isolados mais eficientes foram oriundos do grupo de solo de baixa fertilidade, com destaque para o isolado 49. A menor diversidade rizobiana no grupo de solo de alta fertilidade pode ter sido devida a uma menor dependência destas plantas da fixação biológica de nitrogênio enquanto os solos menos férteis podem ter efetuado uma pressão seletiva, permanecendo os isolados mais eficientes. A cultivar BRS Guariba apresentou maior desempenho na eficiência relativa, demonstrando uma boa especificidade simbiótica entre as estirpes.
24

Silagem de grão de sorgo reidratado com água ou soro de leite / Grain silage of sorghum rehydrated with water or whey

Faustino, Thailson Fernando 30 September 2016 (has links)
Submitted by biblioteca unifenas (biblioteca@unifenas.br) on 2017-05-15T18:46:23Z No. of bitstreams: 1 Thailson Fernando Faustino Dissertacao.pdf: 714335 bytes, checksum: e9b1bc519ff0d96e7bd8cbe84dfe1746 (MD5) / Made available in DSpace on 2017-05-15T18:46:23Z (GMT). No. of bitstreams: 1 Thailson Fernando Faustino Dissertacao.pdf: 714335 bytes, checksum: e9b1bc519ff0d96e7bd8cbe84dfe1746 (MD5) Previous issue date: 2016-09-30 / The objective of this research was to evaluate the nutritional quality of sorghum silage processed and rehydrated with water or whey. The experimental design was a completely randomized 4x2x2 factorial design, with rehydration of the grain in four moisture contents (25, 30, 35 and 40%), rehydration with water or whey and, with or without the addition of bacterial inoculant, totaling 16 treatments with four replicates each. The sorghum grains were ground, rehydrated and conditioned in experimental PVC silos with capacity of 4.5 kg for 90 days, to evaluate the aerobic stability as well as the microbiological and chemical-bromatological characteristics of the silage. The results were submitted to analysis of variance of the statistical program SAS (9.2), and the humidity levels were evaluated by linear and quadratic orthogonal contrasts and, the vehicle of rehydration and inoculant were compared by F test. The use of water compared to the whey in the rehydration decreased the losses by gases, effluents and dry matter of the silages. The increase of moisture in the silages promoted a lower development of fungi and yeasts. The inoculated silages showed higher dry matter contents in relation to the silages without inoculant. The crude protein (CP) concentration in the grain silage of rehydrated sorghum was not altered as a function of the treatments. The addition of inoculant decreases the concentration of acid detergent fiber (ADF), the lowest values being in the silage with 40% moisture with water. Silage rehydrated with whey had higher values of mineral matter, compared to silages rehydrated with water. The use of whey in the rehydration of sorghum grains for silage is a good strategy to avoid its disposal in the environment, and its addition is recommended to the point where the sorghum grain reaches 30% moisture. In addition, it is recommended to use the bacterial inoculant, as it ensures less fermentative loss in the process with greater aerobic stability of the silages. / Objetivou-se com esta pesquisa avaliar a qualidade nutricional da silagem de grão de sorgo processada e reidratada com água ou soro de leite. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 4x2x2, sendo a reidratação do grão em quatro teores de umidade (25, 30, 35 e 40%), a reidratação com água ou soro e com ou sem a adição de inoculante bacteriano, totalizando 16 tratamentos com quatro repetições cada. Os grãos de sorgo foram moídos, reidratados e acondicionados em silos experimentais de PVC com capacidade de 4,5 kg por 90 dias, para então, avaliar a estabilidade aeróbia, bem como as características microbiológicas e químico-bromatológicas da silagem. Os resultados foram submetidos à análises de variância do programa estatístico SAS (9.2), sendo que os níveis de umidade foram avaliados por contrastes ortogonais lineares e quadráticos, e o veículo de reidratação e inoculante foram comparados por teste F. O uso de água comparado com o soro na reidratação diminuiu as perdas por gases, efluentes e matéria seca das silagens. O aumento da umidade nas silagens promoveu menor desenvolvimento de fungos e leveduras. As silagens inoculadas apresentaram teores de matéria seca superiores em relação às silagens sem inoculante. A concentração PB na silagem de grão de sorgo reidratado não foi alterada em função dos tratamentos. A adição de inoculante diminui a concentração de FDA, sendo que os valores mais baixos foram na silagem com 40% de umidade com água. As silagens reidratadas com soro de leite apresentaram maiores valores de matéria mineral, comparadas às silagens reidratadas com água. A utilização de soro de leite na reidratação de grãos de sorgo para ensilagem é uma boa estratégia para evitar seu descarte no meio ambiente, sendo recomendada sua adição até o ponto em que o grão de sorgo atinja 30% de umidade. Além disso, recomenda-se a utilização do inoculante bacteriano, por assegurar menor perda fermentativa no processo com maior estabilidade aeróbia das silagens.
25

Investigation of the possibility for using ZrO2 and ZrSiO4 for Zr additions to liquid ferrosilicon

Vickerfält, Amanda January 2017 (has links)
Ferrosilicon containing 50-75% Si and 1.0-5.0% Zr is used as inoculant in the cast iron industry. Zr can be added to liquid ferrosilicon by use of Zr metal or zirconium ferroalloy (FeSiZr). Then the recovery of Zr, i.e. the fraction of Zr transferred from the additive to the ferrosilicon, as well as the hit rate on specification is high. The aim of this study was to investigate the recovery of Zr from zircon sand, ZrSiO4, and zirconia, ZrO2, in comparison to zirconium ferroalloy when added to liquid ferrosilicon with 75% Si at 1600⁰C.  Also the refining effect of the different additives on Al was investigated. The experiments were carried out by stirring samples of controlled amounts of ferrosilicon and Zr additive in a graphite crucible at 1600⁰C and under inert Ar atmosphere for certain amounts of time. The reaction between ferrosilicon and Zr additive was stopped by rapid cooling of the samples. ICP-OES provided the concentration of Zr and Al and LECO O/N the concentration of O. SEM-ESD was used to examine the microstructures of ferrosilicon and Zr additive after experiments. It was found that ZrO2 was reduced by Si at the particle surface to yield dissolved Zr and ZrSiO4. The ZrSiO4 additive decomposed via two simultaneous reactions, one yielding ZrO2, Si and O2 and the other Zr, Si and O2. The recovery of Zr from ZrO2 and ZrSiO4 was significantly lower than from FeSiZr. Of ZrO2 and ZrSiO4, ZrO2 yielded the highest Zr recovery; the difference was much bigger than predicted by thermodynamics. It was discussed if that could be due to a higher reaction rate of the ZrO2, caused by the smaller size (APS 1 µm compared to d50 91 µm) and larger surface area of this addition. It was also found that utilization of density differences to separate the ferrosilicon and Zr additive did not work for zirconia under the same conditions as it worked for zircon sand, although zirconia has a higher density than zircon sand. The reason was the smaller particle size of the ZrO2 powder. No refining of Al was observed.
26

Assessing the compatibility and aroma production of NT 202 Co-Inoculant with different wine yeasts and additives

Scholtz, Marene 03 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The influence of malolactic fermentation (MLF) in most red and some white wines is one of many factors that determine or influence wine quality, because it affects the flavour and sensory profile of wine. This process is a decarboxylation process conducted by lactic acid bacteria (LAB) such as Oenococcus, Lactobacillus, Pediococcus and Leuconostoc. Mostly Oenococcus oeni, but recently also Lactobacillus plantarum is used in commercial starter cultures and also the first mixed MLF starter culture (NT 202 Co-Inoculant) was commercialized in 2011. The reason for the predominant use of O. oeni and recently L. plantarum is due to their tolerance to the harsh wine environment. Malolactic fermentation leads to a decrease in acidity and an increase in pH that leaves the wine with a softer mouthfeel. Another reason to conduct MLF is the improvement of microbial stability by the removal of malic acid as carbon source. Research focus has recently shifted to the ability of LAB and MLF as well as the interaction of LAB with yeast to alter the wine aroma profile via the modification and/or production of certain aroma compounds. The main goal of this study was to assess the impact of yeast and nutrient addition on the ability of the NT 202 Co-Inoculant to conduct MLF during co-inoculation and to evaluate the aroma compound production in the final wine. The first aim was to evaluate the impact of different red and white wine yeast strains on the ability of the NT 202 Co-Inoculant to conduct MLF during co-inoculation in Chardonnay, Merlot and Shiraz. Malolactic fermentation was unsuccessful in the Chardonnay due to a low pH, but successful in Merlot and Shiraz. Based on the malic acid degradation ability of the NT 202 Co- Inoculant, the yeasts were grouped into three categories: inhibitory, neutral or stimulatory towards MLF. Co-inoculated MLF showed a clear decrease in total fermentation time while yeast strains such as WE 372 and Exotics showed positive compatibility with the NT 202 Co- Inoculant. The impact of the yeast-bacterial combinations on the aroma compound production in the final wine was evaluated. Co-inoculated MLF showed positive aroma changes in the red wines with a general increase in total esters (associated with fruity characters in wine) especially ethyl lactate and diethyl succinate that also contribute to the mouthfeel of the wine. Production of esters, volatile fatty acids and higher alcohols seemed to depend on the yeastand LAB strain used. The NT 202 Co-Inoculant contributed to the monoterpenes produced and MLF led to increased concentrations of diacetyl and acetoin, which are associated with buttery characters in wine. The second aim of this study was to evaluate the impact of wine additives (used during coinoculation) such as yeast- and bacterial nutrients, clarifying- and detoxifying agents on the ability of the NT 202 Co-Inoculant to conduct MLF and to assess their impact on the aroma compound production in the final wine. No negative or positive impact on the malic acid degradation of the NT 202 Co-Inoculant or the resulting aroma compound production was observed for the different wine additives used in this study. The results generated from this study showed that the selection of yeast strains is important as it will influence both the fermentation duration and final wine aroma. / AFRIKAANSE OPSOMMING: Die invloed van appelmelksuurgisting (AMG) in die meeste rooi- en witwyne is een van baie faktore wat wynkwaliteit beïnvloed, omrede dit die geur en sensoriese profiel van wyn beïnvloed. Hierdie proses is 'n dekarboksileringsaksie wat deur melksuurbakterieë (MSB), soos Oenococcus, Lactobacillus, Pediococcus en Leuconostoc, uitgevoer word. Die mees algemene bakterieë wat gebruik word, is Oenococcus oeni, maar onlangs het Lactobacillus plantarum ook na vore getree in die gebruik van kommersiële aanvangskulture. Die eerste gemengde AMGaanvangskultuur (NT 202 Co-Inoculant) is in 2011 gekommersialiseer. Die rede vir die oorheersende gebruik van O. oeni en L. plantarum word toegeskryf aan hul gehardhiedsgraad in ‘n uitdagende wynomgewing. Appelmelksuurgisting lei tot 'n afname in die suurheidsgraad en 'n toename in die pH van die wyn, wat 'n sagter mondgevoel tot gevolg het. Nog 'n rede waarom AMG deurgevoer word, is om die mikrobiese stabiliteit van die wyn te verbeter deur die verwydering van appelsuur as koolstofbron. Die navorsingsfokus het onlangs verskuif na die vermoë van MSB en AMG, sowel as die interaksie van MSB met die gis, om die wynaromaprofiel te verander deur middel van die verandering en/of produksie van sekere aromaverbindings. Die hoofdoel van hierdie studie was om die impak van die gis en voedingstof te evalueer ten opsigte van die vermoë van die NT 202 Co-Inoculant om AMG uit te voer tydens koïnokulasie. Die produksie van aromakomponente in die finale wyn is ook geëvalueer. Die eerste doelwit was om die impak van verskillende rooi- en witwyngisrasse te evalueer ten opsigte van die vermoë van die NT 202 Co-Inoculant om AMG uit te voer tydens koïnokulasie in Chardonnay, Merlot en Shiraz. Appelmelksuurgisting was onsuksesvol in die Chardonnay weens 'n lae pH, maar suksesvol in Merlot en Shiraz. In terme van die appelsuurafbraakvermoë van die NT 202 Co-Inoculant, is die giste in drie kategorieë gegroepeer: inhiberend, neutraal of stimulerend teenoor AMG. Ge-koïnokuleerde AMG het 'n duidelike afname in die totale fermentasietyd getoon, terwyl gisrasse, soos WE 372 en Exotics, ‘n positiewe verenigbaarheid met die NT 202 Co-Inoculant getoon het. Die impak van die gisbakteriële kombinasies op die aromakomponentproduksie in die finale wyn is geëvalueer. Gekoïnokuleerde AMG het positiewe aromaveranderinge in die rooiwyne getoon met 'n algemene toename in die totale esters (wat geassosieer word met vrugtige karakters in wyn), veral etiellaktaat en dietielsuksinaat, wat ook bydra tot die mondgevoel van die wyn. Dit het voorgekom dat produksie van esters, vlugtige vetsure en hoër alkohole moontlik afhanklik kan wees van die gis- en bakteriële ras gebruik. Die NT 202 Co-Inoculant het bygedra tot die monoterpene wat geproduseer is en AMG het gelei tot verhoogde konsentrasies van diasetiel en asetoïen, wat geassosieer word met botteragtige karakters in wyn. Die tweede doelwit van hierdie studie was om die impak van wyntoevoegingsmiddels (wat tydens koïnokulasie gebruik word) bv. gis- en bakteriese voedingstowwe, verhelderingsagente, asook detoksifiserende agente, te evalueer ten opsigte van die vermoë van die NT 202 Co- Inoculant om AMG uit te voer en om hul impak op die produksie van die aromakomponente van die finale wyn te ontleed. Geen negatiewe of positiewe effekte is waargeneem vir die verskillende wyntoevoegingsmiddels, wat in hierdie studie gebruik is, in terme van die appelsuurafbraak van die NT 202 Co-Inoculant of die gevolglike produksie van aromakomponente nie. Hierdie studie se resultate toon dat die keuse van die gisras belangrik is, omdat dit die fermentasietydperk, asook die finale wynaroma, beïnvloed. / Anchor Yeast, Oenobrands, The National Research Foundation and THRIP, for financial support
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Efeitos de L. buchneri e 1-propanol no valor nutritivo de silagens de milho para vacas leiteiras / The effects of Lactobacillus buchneri and 1-propanol on the nutritive value of corn silage for dairy cows

Silva, Janielen da 12 January 2015 (has links)
Lactobacillus buchneri é um microrganismo heterolático capaz de produzir quantidades significativas de ácido acético, que tem ação anti-fúngica e melhora a estabilidade aeróbia de silagens. Além de ácido acético, silagens inoculadas com L. buchneri tipicamente apresentam maiores teores de 1-propanol. Acredita-se que este álcool estaria associado à depressão de consumo de matéria seca (CMS). Assim, o objetivo deste trabalho foi avaliar o efeito da inoculação de silagens de milho com L. buchneri e da suplementação com 1-propanol no desempenho de vacas leiteiras. O experimento foi conduzido no Departamento de Zootecnia da Escola Superior de Agricultura \"Luiz de Queiroz\" (ESALQ/USP). A cultura do milho foi colhida com aproximadamente 35% de matéria seca (MS) e ensilada em bags com capacidade de 40 t. No momento da ensilagem, dois tratamentos foram impostos: controle (C) e L. buchneri 1 × 105 ufc/g (LB). Após 247 dias de armazenamento, os silos foram abertos e o ensaio de lactação foi iniciado. Vinte vacas Holandesas foram alocadas em sete Quadrados Latinos 3 × 3, com períodos de 21 dias (14 d adaptação). As dietas experimentais continham (% MS): 8% de caroço de algodão, 9,5% de polpa cítrica, 18% de farelo de soja, 9,0% de milho moído, 2,5% de premix mineral+vitaminas e 53% de silagem de milho C ou LB ou silagem de milho C + 1,0% de 1-propanol (PROP). O 1-propanol foi diluído em água (1:1) e aspergido na ração total durante a mistura, imediatamente antes da oferta das refeições. Parâmetros de fermentação e composição bromatológica das silagens foram realizadas nos períodos experimentais, assim como ensaio de estabilidade aeróbia. A taxa de desaparecimento de ácido acético, etanol e 1-propanol foram mensuradas em cada período durante a exposição das rações no cocho. O CMS, a produção e a composição de leite, a digestibilidade aparente no trato total, o comportamento ingestivo e o índice de seleção de partículas foram registrados entre os dias 15 e 21 de cada período experimental. Nos mesmos dias, foram realizadas coletas de fluido ruminal para determinação das concentrações de ácidos graxos voláteis e 1-propanol e, de sangue para avaliação das concentrações de glicose e ácidos graxos não esterificados (AGNE). Os dados foram submetidos à análise de variância e as médias comparadas pelo Teste de Tukey-Kramer (α=0,05), utilizando-se o procedimento MIXED do SAS. Os parâmetros de fermentabilidade e a estabilidade aeróbia das silagens foram semelhantes entre os tratamentos. O CMS, a produção e a composição do leite também não diferiram. Entretanto, a digestibilidade da matéria orgânica, foi menor para o tratamento LB. Animais alimentados com 1-propanol apresentaram maior concentração ruminal deste álcool, maior concentração sanguínea de glicose e menor de AGL. A inoculação das silagens com L. buchneri na dose 1 × 105 ufc/g não modifica a qualidade e a estabilidade aeróbia de silagens de milho. A inoculação com L. buchneri na dose 1 × 105 ufc/g e a adição de 1-propanol na dieta não alteraram o desempenho de vacas leiteiras. / L. buchneri is a heterolactic microorganism capable of producing significant amounts of acetic acid that has antifungal action and usually increase the aerobic stability of silage. In addition, silages inoculated with L. buchneri typically exhibit higher levels of 1-propanol. There is a clame that 1-propanol is associated with decreased dry matter intake (DMI). Thus, the objective of this work was to evaluate the effects of inoculating L. buchneri at corn ensiling and supplementing total mixed rations (TMR) with 1-propanol on the performance of lactating dairy cows. The experiment was conducted in the Department of Animal Science, College of Agriculture \"Luiz de Queiroz\" (ESALQ / USP). Corn crop was harvested at 35% DM and ensiled in farm scale bags (40 t/bag). At ensiling, treatments were: control (C) and L. buchneri 1 × 105 cfu/g (LB). After 247 d of storage, silos were opened and the lactation trial was carried out. Twenty Holstein cows housed in a Tie-stall barn were assigned to a replicated 3 × 3 Latin square design, with 21 d periods (14 d adaptation). Diets contained (DM basis): 8% whole cottonseed, 9.5% citrus pulp, 18% soybean meal, 9% dry ground corn, 2.5% premix mineral + vitamins, and 53% corn silage C or LB or corn silage C + 1% of 1-propanol (PROP). The 1-propanol was diluted in water (1:1) and sprayed onto the TMR during mixing, immediately before each feeding. Silage fermentation and chemical composition were evaluatedin each period, as well as the aerobic stability. Fractional disappearance rates of ethanol, acetic acid and 1-propanol were determined in TMR during feedbunk exposure. The DMI, milk yield and composition, total tract digestibility, ingestive behavior and particle sorting index were recorded from d-15 to d-21 in each period.. In addition, rumen fluid and blood were sampled to determine the concentrations of VFA and 1-propanool, and glucose and non-esterified fatty acids (NEFA), respectively. Analysis of variance was performed using the Mixed procedure of SAS and treatment means were compared by Tukey-Kramer test (α = 0.05). Silage fermentability and aerobic stability were similar between treatments. The DMI, milk yield and milk composition did not differ among treatments. However, the organic matter digestibility was lower for the treatment LB. Animals fed 1-propanol had higher ruminal concentration of this alcohol, higher blood glucose and lower blood NEFA. Inoculation of silage with L. buchneri at 1 × 105 cfu/g does not alter fermentation and is not sufficient to improve the aerobic stability of corn silages. The inoculation of silages with L. buchneri at 1 × 105 cfu/g and the supplementation of TMR with 1-propanol do not alter the performance of dairy cows.
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Identifica??o, quantifica??o e inocula??o de fungos micorr?zicos arbusculares no sistema de produ??o de cana-de-a??car / Identification, quantification and inoculation of arbuscular mycorrhizal fungi in the sugarcane production system

FORS, Rosalba Ortega 18 February 2016 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-05-11T19:39:26Z No. of bitstreams: 1 2016 - Rosalba Ortega Fors.pdf: 2620047 bytes, checksum: d7b3d78fdeae080e9bee983dad584881 (MD5) / Made available in DSpace on 2018-05-11T19:39:26Z (GMT). No. of bitstreams: 1 2016 - Rosalba Ortega Fors.pdf: 2620047 bytes, checksum: d7b3d78fdeae080e9bee983dad584881 (MD5) Previous issue date: 2016-02-18 / CNPq / Brazil is the main sugarcane producer worldwide, with the crop accounting for 15% of the total fertilizers used in the country. In this context, the development and application of arbuscular mycorrhizal fungi (AMF) (Phylum Glomeromycota) inoculants represents a promising alternative for increasing the utilization eficiency of chemical fertilizers, mainly the phosphates In the present work a survey of the AMF community was carried out before planting and after harvesting of the "plant cane" in renewal (rotated or not with Brachiaria ruziziensis) and expansion (previously under pasture) areas. A similar assessment was carried out in sugarcane renovation and expansion areas where two experiments of inoculation with diazotrophic bacterias were being conducted. Under greenhouse conditions, two experiments for selecting AMF strains for sugarcane (Variety SP81-3250) in different soils and substrates were carried out. In renewal areas, after maintained sugarcane monocropping, a rotation cycle with B. ruziziensis between the ratoon removal and the new cane planting doesnot influence the AMF species richness. Prolonged monoculture of sugarcane tends to reduce the AMF diversity after the renewal of the sugarcane plantation, but stills quite high compared to other agricultural systems. In pasture areas converted to sugarcane plantation (expansion) the AMF species richness tends to be higher in the first year after the conversion (plant cane) compared to sugarcane renovation areas. The spore density reached the highest values after the "plant cane" harvesting. The AMF isolates with potentiality to compose a mycorrhizal inoculant for sugarcane areAcaulospora colombiana and Claroideoglomus etunicatum which favoured the development of the pre-sprouted seedlings of sugarcane in soil and substrate. Other isolates that promoted the sugarcane seedlings' development ou nutrition, but still need additional studies are Gigaspora margarita, Scutellospora calospora and Rhizophagus clarus. The expansion area soil (with moderate P content) was the most favorable for the sugarcane growth. The Multiplant substrate promoted the highest growth of the seedlings and favored the AMF colonization. The fertillization recommended for sugarcane seedling production inhibited the plants growth, particularly in the substrate Turfa F?rtil. The Sugar Mill substrate stimulated the seedlings growth the least. The rate of dark septate endophytes colonization (DSE) in the sugarcane seedlings of the cultivar SP81-3250 was high, independently of the inoculated AMF isolate. All the AMF isolates tested showed simultaneus colonization with DSE. / O Brasil ? o maior produtor mundial de cana-de-a??car, sendo a cultura respons?vel por 15% dos fertilizantes utilizados no pa?s. Nesse contexto, o desenvolvimento e aplica??o de inoculantes de fungos micorr?zicos arbusculares (FMAs) (Phylum Glomeromycota) representa uma promissora alternativa para incrementara efici?ncia de aproveitamento dos fertilizantes, principalmente os sfatados. No presente trabalho foi realizado um levantamento da comunidade de FMAs pr?-plantio e p?s-colheita da "cana planta" em ?reas de renova??o (rotacionadas ou n?o com Brachiaria ruzizensis) e expans?o (previamente sobre pastagem) do canavial. Uma avalia??o similar foi realizada em ?reas correspondentes a dois experimentos de inocula??o com bact?rias diazotr?ficas. Foram conduzidos, em casa de vegeta??o, dois experimentos de sele??o de linhagens de FMAs para cana-de-a??car (Cultivar SP81-3250) em diferentes solos e substratos. Em ?reas de monocultivo prolongado de cana-de-a??car uma rota??o com B. ruziziensis na ?poca da renova??o n?o influencia a riqueza da comunidade de FMAs. Por?m, a riqueza de FMAs diminui em monocultura prolongada de cana, mas ainda ? elevada comparada com outros sistemas agr?colas. A riqueza de FMAs em pastagem convertida a canavial ? maior na ?cana planta? comparada ? ?reas de renova??o de canavial. As maiores densidades de esporos nas ?reas canavieiras ocorrem ap?s a colheita da ?cana planta?. As linhagens de FMAs com potencialidade para compor um inoculante micorr?zico para cana-de-a??car s?o Acaulospora colombiana Claroideoglomus etunicatum as quais favorecem o desenvolvimento de mudas pr?-brotadas de cana tanto em solo como em substrato. Outras linhagens que precisam de estudos adicionais por promoverem crescimento ou nutri??o de mudas de cana s?o Gigaspora margarita, Scutellospora calospora e Rhizophagus clarus. O solo da ?rea de expans?o, com teores intermedi?rios de P, ? o mais favor?vel para o crescimento da cana-de-a??car. O substrato Multiplant foi o que mais estimulou o crescimento de mudas pr?-brotadas e promove a maior coloniza??o por FMAs. A aduba??o completa recomendada para a produ??o de mudas pr?-brotadas de cana-de-a??car inibiu o crescimento das plantas, particularmente no substrato Turfa F?rtil. O substrato da Usina promoveu o menor crescimento de mudas de cana-de-a??car. A taxa de coloniza??o radicular por DSE nas mudas da cultivar SP81-3250 foi elevada, independentemente da linhagem de FMA inoculada. Todas as linhagens de FMAs avaliadas apresentaram coloniza??o conjunta com DSE.
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MICROSTRUCTURE REFINEMENT AND MECHANICAL PROPERTY IMPROVEMENT OF AZ31 MAGNESIUM ALLOY RESISTANCE SPOT WELDS DUE TO INOCULANTS

Xiao, Lin January 2012 (has links)
Microstructure refinement was observed in the fusion zone of AZ31 magnesium (Mg) alloy resistance spot welds when an inoculant was added, either Ti, Al8Mn5, or Mn. The dependence of inoculant potency on the lattice disregistry between inoculants and matrix, and on the liquid cooling rate was studied. Microstructural characterization was performed via optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thin foils containing the interface of the inoculant particles and Mg matrix were prepared using a focused ion beam (FIB) technique. Columnar dendritic structures in the vicinity of the fusion boundary and equiaxed dendritic structures in the central area were observed in the fusion zone of welds in the SA and SB AZ31Mg alloys from different suppliers. However, the columnar dendritic zone (CDZ) was well restricted, and the width of the CDZ and the diameters of equiaxed dendrites were much smaller in the SA alloy than those in the SB alloy due to the earlier columnar-equiaxed-transition (CET) in the SA alloy. The refined microstructure in the fusion zone of the SA alloy welds is attributed to the pre-existence of the larger Al8Mn5 particles of 4-10 microns in length in the SA alloy which act as an inoculant for alpha-Mg heterogeneous nucleation. Fatigue life and dislocation substructure were compared between the SA and SB welds. The SA welds with the refined microstructure displayed an enhanced fatigue resistance compared to the SB welds, when the interfacial failure took place across the fusion zone. The increased number and dispersion of slip systems in the fine-grained SA welds contributed to the improvement of fatigue life. The well-developed columnar dendritic grains were successfully restricted and the coarse equiaxed dendritic grains were efficiently refined by intentionally adding Ti or Mn inoculant particles into the as-received SB alloy welds. The Ti and Mn particles of about 8μm diameter were observed to promote the nucleation of alpha-Mg grains during welding. TEM examinations showed the existence of local orientation relationships between the respective inoculants Ti, Mn, and Al8Mn5 with the Mg matrix. The further lattice matching was observed between the Al8Mn5 particles and Mg. The diameter of the added inoculant should be larger than 1.8 microns to make it a potent inoculant based on the thermodynamic calculation. Microstructural examinations of samples with different inoculant additions and under different cooling rates showed that the inoculant potency was high for the Ti inoculant, medium for the Al8Mn5, but low for the Mn, when the cooling rate was low. This order in the decrease of grain refinement efficiency is inversely proportional with the order of crystallographic lattice disregistry between inoculants and matrix, which is calculated based on a crystallographic matching model. This implies that the lattice disregistry determines the potency of inoculants at the low cooling rates. In comparison, the lattice disregistry did not influence the heterogeneous nucleation, when the cooling rate was high. It could be inferred that an extremely high cooling rate produces a large supercooling, and provides a sufficient driving force for heterogeneous nucleation.
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MICROSTRUCTURE REFINEMENT AND MECHANICAL PROPERTY IMPROVEMENT OF AZ31 MAGNESIUM ALLOY RESISTANCE SPOT WELDS DUE TO INOCULANTS

Xiao, Lin January 2012 (has links)
Microstructure refinement was observed in the fusion zone of AZ31 magnesium (Mg) alloy resistance spot welds when an inoculant was added, either Ti, Al8Mn5, or Mn. The dependence of inoculant potency on the lattice disregistry between inoculants and matrix, and on the liquid cooling rate was studied. Microstructural characterization was performed via optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thin foils containing the interface of the inoculant particles and Mg matrix were prepared using a focused ion beam (FIB) technique. Columnar dendritic structures in the vicinity of the fusion boundary and equiaxed dendritic structures in the central area were observed in the fusion zone of welds in the SA and SB AZ31Mg alloys from different suppliers. However, the columnar dendritic zone (CDZ) was well restricted, and the width of the CDZ and the diameters of equiaxed dendrites were much smaller in the SA alloy than those in the SB alloy due to the earlier columnar-equiaxed-transition (CET) in the SA alloy. The refined microstructure in the fusion zone of the SA alloy welds is attributed to the pre-existence of the larger Al8Mn5 particles of 4-10 microns in length in the SA alloy which act as an inoculant for alpha-Mg heterogeneous nucleation. Fatigue life and dislocation substructure were compared between the SA and SB welds. The SA welds with the refined microstructure displayed an enhanced fatigue resistance compared to the SB welds, when the interfacial failure took place across the fusion zone. The increased number and dispersion of slip systems in the fine-grained SA welds contributed to the improvement of fatigue life. The well-developed columnar dendritic grains were successfully restricted and the coarse equiaxed dendritic grains were efficiently refined by intentionally adding Ti or Mn inoculant particles into the as-received SB alloy welds. The Ti and Mn particles of about 8μm diameter were observed to promote the nucleation of alpha-Mg grains during welding. TEM examinations showed the existence of local orientation relationships between the respective inoculants Ti, Mn, and Al8Mn5 with the Mg matrix. The further lattice matching was observed between the Al8Mn5 particles and Mg. The diameter of the added inoculant should be larger than 1.8 microns to make it a potent inoculant based on the thermodynamic calculation. Microstructural examinations of samples with different inoculant additions and under different cooling rates showed that the inoculant potency was high for the Ti inoculant, medium for the Al8Mn5, but low for the Mn, when the cooling rate was low. This order in the decrease of grain refinement efficiency is inversely proportional with the order of crystallographic lattice disregistry between inoculants and matrix, which is calculated based on a crystallographic matching model. This implies that the lattice disregistry determines the potency of inoculants at the low cooling rates. In comparison, the lattice disregistry did not influence the heterogeneous nucleation, when the cooling rate was high. It could be inferred that an extremely high cooling rate produces a large supercooling, and provides a sufficient driving force for heterogeneous nucleation.

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