449 research outputs found
Recent Developments and Future Directions in Flow Visualization: Experiments and Techniques
No full textFlow visualization has long been a critical tool for understanding complex fluid dynamics in both natural and engineered systems [...
Relating quantitative soil structure metrics to saturated hydraulic conductivity
No full textSoil structure affects saturated hydraulic conductivity (Ks) by creating highly conductive macropores that preferentially transmit soil water. In this study, we explore the relationship between Ks and macropores in an Oxyaquic Vertic Argiudoll in northeastern Kansas. Macropores were quantified from an excavation wall using multistripe laser triangulation (MLT) scanning. Soil water contents were measured at four depths within a soil lysimeter installed within 2 meters of the MLT-scanned soil profile and adjacent to an Ameriflux tower monitoring precipitation, air temperature, and solar radiation. Selected hydraulic properties of soil horizons within the lysimeter were optimized to water content data using a Markov chain Monte Carlo technique in combination with the mobile-immobile water (MIM) model in HYDRUS-1D. Estimates of Ks varied between 4198 cm d-1 in the A horizon and 0.6 cm d-1 in a 2Btss2 horizon with strongly expressed wedge structure. Approximately 87% of the variation in Ks was explained by the geometric mean of the widths of pores quantified with the MLT technique and modified by the coefficient of extensibility (COLE). The use of COLE allows the widths of the macropores obtained at dry conditions to be approximated at saturation. Two models that predict Ks from either texture or water retention data resulted in Ks estimates that were similar to each other, but significantly lower than Ks values predicted with MIM in horizons where structural pores dominate water flow. This technique shows a great deal of promise in better understanding and predicting the relationship of soil structure to water flow.Peer reviewe
sj-tif-1-cll-10.1177_09636897221081479 – Supplemental material for Evaluating the Effect of Circ-Sirt1 on the Expression of SIRT1 and Its Role in Pathology of Pulmonary Hypertension
No full textSupplemental material, sj-tif-1-cll-10.1177_09636897221081479 for Evaluating the Effect of Circ-Sirt1 on the Expression of SIRT1 and Its Role in Pathology of Pulmonary Hypertension by Wenjie Diao, Ge Liu, Chao Shi, Yiyao Jiang, Haihui Li, Jinjin Meng, Yu Shi, Mingming Chang and Xuegang Liu in Cell Transplantation</p
sj-docx-2-cll-10.1177_09636897221081479 – Supplemental material for Evaluating the Effect of Circ-Sirt1 on the Expression of SIRT1 and Its Role in Pathology of Pulmonary Hypertension
No full textSupplemental material, sj-docx-2-cll-10.1177_09636897221081479 for Evaluating the Effect of Circ-Sirt1 on the Expression of SIRT1 and Its Role in Pathology of Pulmonary Hypertension by Wenjie Diao, Ge Liu, Chao Shi, Yiyao Jiang, Haihui Li, Jinjin Meng, Yu Shi, Mingming Chang and Xuegang Liu in Cell Transplantation</p
Varieties of alternatives
No full textThis dissertation concerns two focus particles (jiu, dou) and wh-expressions (shenme ‘what’, na geren ‘which person’) in Mandarin Chinese. These items are systematically ‘ambiguous’ and have played important roles in various aspects of Mandarin grammar. An idea based on alternatives and varieties of alternatives in particular – following Chierchia’s 2013 analysis of the polarity system – is pursued to account for the systematic ambiguities. Unambiguous semantics of jiu, dou and wh-expressions is maintained and ‘ambiguity’ explained through varieties of alternatives interacting with other independently motivated aspects of the structure they occur in. A better understanding of a large array of phenomena that involve these items – exhaustivity, distributivity, questions and conditionals – is achieved.Ph.D.Includes bibliographical referencesby Mingming Li
Flow Visualization
No full text"Flow Visualization: Experiments and Techniques", compiles cutting-edge research and innovative methodologies that address the challenges of analyzing fluid dynamics in industrial and scientific contexts. Tailored for researchers, engineers, and graduate students in fluid mechanics and related disciplines, this work emphasizes practical advancements in spatial resolution, dynamic range, and predictive modeling. Contributions from leading experts provide insights into data assimilation, emerging visualization tools, and interdisciplinary collaboration.This Reprint is not just a compilation of research—it is a roadmap for the future of fluid-flow studies. It brings together latest research from leading experts in the field, ensuring readers are exposed to the most up-to-date knowledge and techniques. Flow visualization is vital for aircraft design for those in the aerospace industry. Understanding how air flows around an aircraft's wings and fuselage can lead to more fuel-efficient designs and enhanced flight performance. In the biomedical field, visualizing blood flow in the human body helps in the diagnosis and treatment of various cardiovascular diseases.Whether you are looking to expand your research horizons, enhance your engineering skills, or simply gain a deeper understanding of the fascinating world of fluid dynamics, this reprint is the perfect companion in the ever-evolving field of fluid flow visualization
Experimental Study of Two-Phase Cavitating Flows and Data Analysis
No full textCavitation can be defined as the breakdown of a liquid (either static or in motion) medium under very low pressure. The hydrodynamic happened in high-speed flow, where local pressure in liquid falls under the saturating pressure thus the liquid vaporizes to form the cavity. During the evolution and collapsing of cavitation bubbles, extreme physical conditions like high-temperature, high-pressure, shock-wave, and high-speed micro-jets can be generated. Such a phenomenon shall be prevented in hydraulic or astronautical machinery due to the induced erosion and noise, while it can be utilized to intensify some treatment processes of chemical, food, and pharmaceutical industries, to shorten sterilization times and lower energy consumption. Advances in the understanding of the physical processes of cavitating flows are challenging, mainly due to the lack of quantitative experimental data on the two-phase structures and dynamics inside the opaque cavitation areas. This dissertation is aimed at finding out the physical mechanisms governing the cavitation instabilities and making contributions in controlling hydraulic cavitation for engineering applications. In this thesis, cavitation developed in various convergent-divergent (Venturi) channels was studied experimentally using the ultra-fast synchrotron X-ray imaging, LIF Particle Image Velocimetry, and high-speed photography techniques, to (1) investigate the internal structures and evolution of bubble dynamics in cavitating flows, with velocity information obtained for two phases; (2) measure the slip velocity between the liquid and the vapor to provide the validation data for the numerical cavitation models; (3) consider the thermodynamic effects of cavitation to establish the relation between the cavitation extent and the fluid temperature, then and optimize the cavitation working condition in water; (4) seek the coherent structures of the complicated high-turbulent cavitating flow to reduce its randomness using data-driven methods.Doctor of PhilosophyWhen the pressure of a liquid is below its saturation pressure, the liquid will be vaporized into vapor bubbles which can be called cavitation. In many hydraulic machines like pumps, propulsion systems, internal combustion engines, and rocket engines, this phenomenon is quite common and could induce damages to the mechanical systems. To understand the mechanisms and further control cavitation, investigation of the bubble inception, deformation, collapse, and flow regime change is mandatory. Here, we performed the fluid mechanics experiment to study the unsteady cavitating flow underlying physics as it occurs past the throat of a Venturi nozzle. Due to the opaqueness of this two-phase flow, an X-ray imaging technique is applied to visualize the internal flow structures in micrometer scales with minor beam scattering. Finally, we provided the latest physical model to explain the different regimes that appear in cavitation. The relationship between the cavitation length and its shedding regimes, and the dominant mechanism governing the transition of regimes are described. A combined suppression parameter is developed and can be used to enhance or suppress the cavitation intensity considering the influence of temperature
Visualization studies on evidence-based medicine domain knowledge (series 2): structural diagrams of author networks.
No full textOBJECTIVE: To investigate the output of evidence-based medicine (EBM) researchers in China and elsewhere by examining the EBM domains they work within and the networks that exist among them; using visualization methods to analyze these relationships. This maps the current situation and helps with the identification of areas for future growth. METHODS: We used co-citation matrixes with Pathfinder networks and hierarchical clustering algorithms, and constructed a co-author matrix which were analyzed with a whole network approach. The analyzed matrixes were visualized with the UCINET program. RESULTS: Much of the development of EBM has been centered around three authors, David Sackett, Gordon Guyatt and L Manchikanti, within three different clusters. The main authors of EBM articles in China were divided into nine academic domains. The relations among core authors of articles indexed by the Science Citation Index (SCI) was loose. There was a stronger co-authorship network among core authors in the Chinese literature, with three groups and 21 cliques. Nine distinct academic communities appeared to have formed around Li Youping, Liu Ming and Zhang Mingming. CONCLUSION: The EBM literature contains several key clusters, with universities in high-income countries being the source of the majority of articles. Outside China, McMaster University in Canada, the original home of EBM, is the dominant producer of EBM publications. In China, Sichuan University is the main source of EBM publications. The EBM cooperation network in China is comprised of three major groups, the largest and most productive in this sample is led by Li Youping with Liu Ming, Zhang Mingming, Li Jing, Wang Li, Wu Taixiang, and Liu Guanjian as central members
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