Search results for "grain"
showing 10 items of 752 documents
P2-551: MIGRAINE, COGNITIVE DECLINE, AND DEMENTIA IN OLD AGE: A POPULATION-BASED STUDY
2019
Quantification of the microstructural evolution of polycrystalline fabrics using FAME: Application to in situ deformation of ice
2014
Abstract In geology, glaciology and material science new technological advances result in an ever increasing amount of data and datasets, in particular when in situ experiments are conducted. Rapid, rigorous and reliable statistical treatment is needed to allow researchers to access these large datasets for further analysis. Here, we present FAME (Fabric Analyser based Microstructure Evaluation), a suite of Matlab® scripts that utilize the Matlab® open-source toolboxes MTEX and PolyLX (optional) for rapid quantification of thin section data. The data has been collected using an automated Fabric Analyser at a spatial resolution of 5 μm/pixel. From the dataset, grain maps are reconstructed an…
Review of the relationship between aggregates geology and Los Angeles and micro-Deval tests
2021
Rock aggregates constitute the enormous volume of inert construction material used around the globe. The petrologic description as igneous, sedimentary, and metamorphic types establishes the intrinsic formation pattern of the parent rock. The engineering properties of these rocks vary due to the differences in the transformation process (e.g. hydrothermal deposits) and weathering effect. The two most common mechanical tests used to investigate the performance of aggregates are the Los Angeles (LA) and micro-Deval (MD) tests. This study reviewed the geological parameters (including mineralogy, grain and crystal size, grain shape, and porosity) and the relationship to Los Angeles and micro-De…
Modeling of anisotropic grain growth in minerals
2001
The role of surface energy anisotropy during grain growth is investigated using both physical experiments on octachloropropane and numerical experiments using the Elle microstructural modelling system. In particular the effects of anisotropy on growth rates, grain shapes and lattice preferred orientations are analysed. Anisotropic growth in thin polycrystalline sheets of octachloropropane is found to systematically remove certain c-axis orientations from the sample, without obviously modifying the grain shapes. By comparison with equivalent numerical experiments, we can explain these observations with a simple boundary layer model that treats each side of each grain boundary as an independe…
The role of nanopowder particle surfaces and grain boundary defects in the sintering of ZnO ceramics
2012
This work focuses on the characteristics of sintered ZnO ceramics and explores the role of source powder morphology in the process of sintering. The source ZnO powders had grained (d = 100 nm) and tetrapod-like (d=50-100 nm, l=3−10 μm) morphologies, they were compacted and sintered at 1200° C. The results have shown that ceramics sintered from the grained powder exhibit relatively high (8%) porosity at grain boundaries and as cavities within grains, which facilitates brittleness. Photoluminescence spectra for these ceramics besides a narrow exitonic band contain a broad "green" luminescence band attributed to defect states. The second ceramics sintered from the tetrapod-like powder has lowe…
Solubility and microstructural development of TiO2-containing 3Al2O3·2SiO2 and 2Al2O3·SiO2 mullites obtained from single-phase gels
2007
Abstract The interdependence of the titanium oxide amount and the anisotropic growth of mullites prepared from single-phase gels were investigated. Gels with stoichiometries 3(Al2−xTixO3)·2(SiO2) and 2(Al2−xTixO3)·(SiO2), with 0 ≤ x ≤ 0.15 were prepared by the semialkoxide method. Gels and specimens heated at temperatures between 1200 and 1600 °C were characterized by using infrared spectroscopy (IR), X-ray diffraction (XRD) and transmission and field emission scanning electron microscopies (TEM and FESEM). Al2TiO5 as minor impurity was detected in both series of mullites for gel precursor compositions x = 0.10 and x = 0.15, obtained at temperatures between 1200 and 1600 °C. Variations of l…
Comparison of analytical methods and AI tools for material characterisation in hot forming
2002
Abstract Hot forming processes probably represent the most ancient of forming operations and what is more they are still today commonly used in modern mechanical industry in order to obtain sound parts, achieving large deformations with a limited required power. Hot metal forming operations are characterised by a large number of physical and thermal phenomena which have to be taken into account in order to model and design the processes themselves. Actually several thermally activated phenomena occur during the forming processes such as recovery, recrystallisation, grain growth, precipitation, allotropic transformations, etc. In this paper the comparison between an analytical method based o…
Effect of inoculation with selected Bradyrhizobium spp. on the survival and growth of Acacia mangium saplings after 20 months in the field
1999
This work was designed to test the long-term effect of the inoculation of #Acacia mangium# seedlings with 10 selected strains of #Bradyrhizobium spp.#. The percentage of survival of seedlings inoculated with any of the #Bradyrhizobium# strains was increased by 10% as compared to the control plants. However, out of the 10 #Bradyrhizobium# strains tested, only 3 strains, Aust l3c, Lu 4 and Tel 8, belonging to the phylogenelic group 1, significandy enhanced the growth of #A. mangium# after 20 months in the field. For the first time, inoculation with indigenous Malaysian strains #Bradyrhizobium# such as Tel 8 and Lu 4 at the seedling stage is reported to produce enhanced and sustained growth an…
Die Erfassung von Triggerempfindlichkeit und -vermeidung bei primären Kopfschmerzen: Entwicklung und psychometrische Erprobung einer deutschen Versio…
2019
<b><i>Hintergrund:</i></b> Die Vermeidung von Kopfschmerzauslösern kann zur Entwicklung primärer Kopfschmerzerkrankungen führen. Daraus können verhaltenstherapeutische Behandlungsoptionen abgeleitet werden, die auf einen differenzierten Umgang mit Kopfschmerztriggern abzielen. Zur Unterstützung der Therapieevaluation und -planung bei primären Kopfschmerzen wurde im englischsprachigen Raum der Fragebogen <i>Headache Triggers Sensitivity and Avoidance Questionnaire</i> (HTSAQ) entwickelt. <b><i>Patienten und Methoden:</i></b> Der HTSAQ wurde ins Deutsche übersetzt. Anhand einer Stichprobe von Patienten der Migräne- und Kopfschmerzk…
Molecular Identification and Mycotoxin Production by Alternaria Species Occurring on Durum Wheat, Showing Black Point Symptoms
2020
Black point is a fungal disease of wheat, mainly associated with mycotoxigenic Alternaria species. Affected wheat kernels are characterized by dark brown discolouration of the embryo region and reduction of grain quality. Potential risk is the possible accumulation of Alternaria mycotoxins, alternariol (AOH), alternariol-monomethyl ether (AME), tenuazonic acid (TA), and altenuene (ALT), provided by haemato-toxic, genotoxic, and mutagenic activities. One hundred and twenty durum wheat samples belonging to 30 different genotypes grown in Bologna and Modena areas, in Italy, showing black point symptoms, were analyzed for Alternaria species and their mycotoxin contamination. Alternariol was sel…