Interactive visualization of computational fluid dynamics data.

This thesis describes a literature study and a practical research in the area of flow visualization, with special emphasis on the interactive visualization of Computational Fluid Dynamics (CFD) datasets. Given the four main categories of flow visualization methodology; direct, geometric, texture-based and feature-based flow visualization, the research focus of our thesis is on the direct, geometric and feature-based techniques. And the feature-based flow visualization is highlighted in this thesis. After we present an overview of the state-of-the-art of the recent developments in the flow visualization in higher spatial dimensions (2.5D, 3D and 4D), we propose a fast, simple, and interactive glyph placement algorithm for investigating and visualizing boundary flow data based on unstructured, adaptive resolution boundary meshes from CFD dataset. Afterward, we propose a novel, automatic mesh-driven vector field clustering algorithm which couples the properties of the vector field and resolution of underlying mesh into a unified distance measure for producing high-level, intuitive and suggestive visualization of large, unstructured, adaptive resolution boundary CFD meshes based vector fields. Next we present a novel application with multiple-coordinated views for interactive information-assisted visualization of multidimensional marine turbine CFD data. Information visualization techniques are combined with user interaction to exploit our cognitive ability for intuitive extraction of flow features from CFD datasets. Later, we discuss the design and implementation of each visualization technique used in our interactive flow visualization framework, such as glyphs, streamlines, parallel coordinate plots, etc. In this thesis, we focus on the interactive visualization of the real-world CFD datasets, and present a number of new methods or algorithms to address several related challenges in flow visualization. We strongly believe that the user interaction is a crucial part of an effective data analysis and visualization of large and complex datasets such as CFD datasets we use in this thesis. In order to demonstrate the use of the proposed techniques in this thesis, CFD domain experts reviews are also provided

Molecular subgroups of adult medulloblastoma: a long-term single-institution study

Background Recent transcriptomic approaches have demonstrated that there are at least 4 distinct subgroups in medulloblastoma (MB); however, survival studies of molecular subgroups in adult MB have been inconclusive because of small sample sizes. The aim of this study is to investigate the molecular subgroups in adult MB and identify their clinical and prognostic implications in a large, single-institution cohort. Methods We determined gene expression profiles for 13 primary adult MBs. Bioinformatics tools were used to establish distinct molecular subgroups based on the most informative genes in the dataset. Immunohistochemistry with subgroup-specific antibodies was then used for validation within an independent cohort of 201 formalin-fixed MB tumors, in conjunction with a systematic analysis of clinical and histological characteristics. Results Three distinct molecular variants of adult MB were identified: the SHH, WNT, and group 4 subgroups. Validation of these subgroups in the 201-tumor cohort by immunohistochemistry identified significant differences in subgroup-specific demographics, histology, and metastatic status. The SHH subgroup accounted for the majority of the tumors (62%), followed by the group 4 subgroup (28%) and the WNT subgroup (10%). Group 4 tumors had significantly worse progression-free and overall survival compared with tumors of the other molecular subtypes. Conclusions We have identified 3 subgroups of adult MB, characterized by distinct expression profiles, clinical features, pathological features, and prognosis. Clinical variables incorporated with molecular subgroup are more significantly informative for predicting adult patient outcome

Optimization of Ganoderma leucocontextum Fermented Tea Medium Formula Based on High-yield Extracellular Crude

To investigate the optimal nutritional conditions and their contributing factors for the secretion of extracellular crude polysaccharides with Ganoderma leucocontextum on a liquid tea substrate, this study optimized the nutritional conditions of its extracellular crude polysaccharides formation by orthogonal experiment and analysis of variance on the basis of the single-factor test, and explored the relevance between its liquid culture characteristics and the secretion of extracellular crude polysaccharides using correlation and path analyses. The results of study revealed that the greatest output of extracellular crude polysaccharide (1.49±0.33 g/L) was achieved on a tea culture medium of 50 g/L potato, 40 g/L glucose, 3 g/L laterite, 20 g/L Pu'er tea and 0.075 mm tea powder particle size, and was affected by each nutritional condition in the descending order of glucose>tea variety>laterite>potato>tea powder particle size. Moreover, the secretion of extracellular crude polysaccharides in G. leucocontextum was significantly impacted by the soluble solids of the fermentation broth and the number of mycelium balls, with the former having the greatest indirect effect while the latter, the greatest direct and combined effect on it. In conclusion, the nutritional conditions (variety, concentration, particle size, etc.) of the tea culture medium and the liquid culture characteristics of G. leucocontextum exerted a significant and interactive effect on the secretion of extracellular crude polysaccharides, and the aforesaid results may provide a theoretical reference for extraction of polysaccharides from this mushroom and development of it as functional foods

Experiment on the promoting-inhibiting effects on methane explosion by using haloalkanes

Methane explosion is one of the major disasters that seriously threaten the safety of coal mine production, the development of efficient methane explosion suppression technology can effectively improve the prevention and control level of methane explosion accidents, and its focus is on the function of explosion suppression materials. In order to systematically study the effect of typical haloalkanes extinguishing agents on methane explosion, the effects of typical haloalkanes such as heptafluoropropane (C3HF7), hexafluoropropane (C3H2F6) and trifluoromethane (CHF3) on the ignition and explosion characteristics of methane were systematically studied by combining experimental tests and theoretical analysis. The effects of haloalkanes on methane explosion pressure parameters and laminar burning velocity were tested by a 20 L spherical explosive vessel and a self-developed Bunsen burner laminar flame propagation velocity system. The variation laws of peak explosion pressure, maximum pressure rise rate, laminar burning velocity, and laminar flame morphology evolution were obtained. The results show that with the increase of the added volume fraction, the haloalkanes had a double effect of promoting and inhibiting the methane explosion process. Under the chemical equivalent condition, only C3HF7 can first promote and then inhibit the peak explosion pressure and maximum pressure rise rate of methane, while CHF3 and C3H2F6 can inhibit the effect. The three haloalkanes all showed inhibition on the combustion rate of methane laminar flow. In the oxygen-poor condition, the three haloalkanes inhibited the peak explosion pressure, the maximum pressure boost rate, and the laminar burning velocity of methane. In general, C3H2F6 and C3HF7 have better inhibition effects on methane explosion pressure characteristic parameters and laminar burning velocity than CHF3. The theoretical analysis results show that the double effect of promoting and inhibiting the haloalkanes with the increase of the mixture volume fraction can be attributed to the competition between the improvement of the heat release characteristics of the system reaction and the inhibition of the key free radicals such as H, O, and OH by the main intermediates containing F. The results of this paper provide a theoretical basis for the theoretical research and technical development of methane explosion prevention and control

Role of corticotropin-releasing hormone in the impact of chronic stress during pregnancy on inducing depression in male offspring mice

This is an accepted manuscript of an article published by Elsevier in Brain Research on 30/07/2020, available online: https://doi.org/10.1016/j.brainres.2020.147029 The accepted version of the publication may differ from the final published version.This work was supported by the National Natural Science Foundation of China (grant no. 81773452).Published versio

Higher Dimensional Vector Field Visualization: A Survey

Vector field visualization research has evolved very rapidly over the last two decades. There is growing consensus amongst the research community that the challenge of two-dimensional vector field visualization is virtually solved as a result of the tremendous amount of effort put into this problem. Two-dimensional flow, both steady and unsteady can be visualized in real-time, with complete coverage of the flow without much difficulty. However, the same cannot be said of flow in higher-spatial dimensions, e.g. surfaces in 3D (2.5D) or volumetric flow (3D). We present a survey of higher-spatial dimensional flow visualization techniques based on the presumption that little work remains for the case of two-dimensional flow whereas many challenges still remain for the cases of 2.5D and 3D domains. This survey provides the most up-to-date review of the state-of-the-art of flow visualization in higher dimensions. The reader is provided with a high-level overview of research in the field highlighting both solved and unsolved problems in this rapidly evolving direction of research