178 research outputs found

    Ultrasonic Velocity Profiler for the Measurement of a Bubbly Flow Velocity Vector in Small Channels

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    The multi-dimensional velocity distribution of coolant in bubbly flow within the fuel rod bundles of the reactor core in boiling water reactors (BWRs) is elucidated by experimental investigation in this study. Since a measurement technique is required for such an investigation, this paper proposes the development of an ultrasonic velocity profiler (UVP). The combination of special ultrasonic transducers and modified signal processing on the UVP is proposed to obtain a multi-dimensional velocity vector of the bubbles and liquid in bubbly flow. The ability of the proposed technique is demonstrated by performing an experiment in swirling bubbly flow and its applicability confirmed by comparing the results with another technique. The sound pressure distribution in the narrow channel of the rod bundle is then measured prior to the verification of the ultrasonic wave emitted through a small channel. The echo signal reflected from reflectors dispersed in the liquid, bubble, and tracer particles in the small channel of the rod bundle indicates that the proposed UVP can be applied in this application with a low level of multi-reflection. Finally, the UVP system is demonstrated to measure the velocity vector of bubbly flow in the narrow flow channel on the rod bundle, and the velocity vector of the bubble and liquid obtained simultaneously

    Ultrasonic Velocity Profiler for the Measurement of a Bubbly Flow Velocity Vector in Small Channels

    Get PDF
    The multi-dimensional velocity distribution of coolant in bubbly flow within the fuel rod bundles of the reactor core in boiling water reactors (BWRs) is elucidated by experimental investigation in this study. Since a measurement technique is required for such an investigation, this paper proposes the development of an ultrasonic velocity profiler (UVP). The combination of special ultrasonic transducers and modified signal processing on the UVP is proposed to obtain a multi-dimensional velocity vector of the bubbles and liquid in bubbly flow. The ability of the proposed technique is demonstrated by performing an experiment in swirling bubbly flow and its applicability confirmed by comparing the results with another technique. The sound pressure distribution in the narrow channel of the rod bundle is then measured prior to the verification of the ultrasonic wave emitted through a small channel. The echo signal reflected from reflectors dispersed in the liquid, bubble, and tracer particles in the small channel of the rod bundle indicates that the proposed UVP can be applied in this application with a low level of multi-reflection. Finally, the UVP system is demonstrated to measure the velocity vector of bubbly flow in the narrow flow channel on the rod bundle, and the velocity vector of the bubble and liquid obtained simultaneously

    Development of an instantaneous velocity-vector-profile method using conventional ultrasonic transducers

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    A velocity vector profile technique based on an ultrasound pulsed Doppler method can enrich the information on the flow field. However, it has shown low availability because a new design of special transducers is required for each measurement case. This study proposes a new method of profiling the velocity vectors using conventional ultrasound transducers that are widely supplied to ultrasound velocity profile users. We constructed a configuration of transducers to minimize the uncertainty of the detection points at the receivers, and a measurable distance was theoretically determined by the configuration. Two feasibility tests were carried out. One was a test for the assessment of the measurable distance, which agreed well with the theoretical distance. The other was the evaluation of the measurement of 2D velocity vectors by the new method, and it was performed in a towing tank facility without the velocity fluctuation. From the evaluation, it was confirmed that the measured vectors showed good agreement with the reference values, and their accuracy and precision were competitive compared to previous studies. In order to demonstrate this, the developed method was applied to two unsteady flows. The results clarified that the proposed method guarantees high availability and accuracy for the velocity vector profiles

    Chemical and physical dynamics of marine pockmarks with insights into the organic carbon cycling on the Malin Shelf and in Dunmanus Bay, Ireland.

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    Pockmarks are specific type of marine geological setting resembling craters or pits. They are considered surface expression of fluid flow in the marine subsurface. Pockmarks are widespread in the aquatic environment but the understanding of their formation mechanisms, relationship with marine macro- and micro-biota and their geochemistry remains limited. Despite numerous findings of these features in Irish waters they received little attention and remain poorly studied. In this work extensive geophysical data sets collected by the Irish National Seabed Survey and its successor the INFOMAR project as well in situ sediment samples were utilized to provide baseline information on the nature of some of these features, the processes they are fuelled by and their geochemical characteristics. Pockmarks from open shelf (Malin Shelf) and bay, fjord like environment (Dunmanus Bay) are compared and theories of their formation are formulated. Sediment from these features was extensively studied utilizing advanced geotechnical and geochemical tools to describe and quantify processes taking place in the subsurface. Organic matter was characterized on a molecular level by combined biomarker and advanced Nuclear Magnetic Resonance approach

    Out of Site but Not Out of Mind: Submerged Prehistoric Landscapes on the Northwestern Gulf of Mexico Outer Continental Shelf

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    Archaeological sites are more important than simply the artifacts they contain. Locations of human occupation and activity form a pattern that can provide information about perceptions of the landscape, decisions about resources, or preferences. Explaining this “perceived” environment is one of archaeology’s goals in explaining past human behavior. In order to address these goals, archaeologists must first identify elements of the “real” landscape, including the geographical environment, its resources, and evidence of human modification. Only after these real elements have been identified can the perceived environment be explored. On the outer continental shelf of the northwestern Gulf of Mexico, formerly subaerial geographical environments are now submerged offshore of Texas and Louisiana. These areas could have been occupied by Paleoindian or Early Archaic populations prior to final inundation related to sea-level rise following the last glacial maximum. Due to sediment accretion related to transgression, as well as active sedimentation in the marine environment, the formerly subaerial surface is now buried below the seafloor. This dissertation discusses the use of geophysical data in identifying environments, resources, and evidence of environmental modification at areas that are currently buried below the seafloor on the outer continental shelf. The use of methods and data grounded in physical geography can ultimately add to patterns of past human behavior

    Proceeding Of Mechanical Engineering Research Day 2016 (MERD’16)

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    This Open Access e-Proceeding contains a compilation of 105 selected papers from the Mechanical Engineering Research Day 2016 (MERD’16) event, which is held in Kampus Teknologi, Universiti Teknikal Malaysia Melaka (UTeM) - Melaka, Malaysia, on 31 March 2016. The theme chosen for this event is ‘IDEA. INSPIRE. INNOVATE’. It was gratifying to all of us when the response for MERD’16 is overwhelming as the technical committees received more than 200 submissions from various areas of mechanical engineering. After a peer-review process, the editors have accepted 105 papers for the e-proceeding that cover 7 main themes. This open access e-Proceeding can be viewed or downloaded at www3.utem.edu.my/care/proceedings. We hope that these proceeding will serve as a valuable reference for researchers. With the large number of submissions from the researchers in other faculties, the event has achieved its main objective which is to bring together educators, researchers and practitioners to share their findings and perhaps sustaining the research culture in the university. The topics of MERD’16 are based on a combination of fundamental researches, advanced research methodologies and application technologies. As the editor-in-chief, we would like to express our gratitude to the editorial board and fellow review members for their tireless effort in compiling and reviewing the selected papers for this proceeding. We would also like to extend our great appreciation to the members of the Publication Committee and Secretariat for their excellent cooperation in preparing the proceeding of MERD’16

    2015 Abstract Book

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    Sustainable Functional Food Processing

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    Functional nutrition is deeply connected with healthy lifestyle and sustainable food production, due to its positive health benefits and the use of economically underexplored and natural raw materials. Expectedly, it appeals to large number of interested consumers while becoming lucrative segment of the food industry with a fast-growing market fueled by new sociodemographic trends. Accordingly, functional juices and beverages made of indigenous fruits are interesting niche for various food market stakeholders. Here, biologically active compounds (BACs) and probiotics that have positive health effects in functional foods (juices) are mostly thermolabile. This is especially important for industry that still employs classical heat treatments (e.g., pasteurization), while being concerned with degradation of food quality in the final products. To prevent this, focus is on designing economic and ecological technologies that are able to preserve nutritional and sensory quality while maintaining microbiological stability in products. Such approaches are based on low-energy consumption and low-impact processing, e.g. “hurdle technology” that combines advanced and conventional methods (e.g., high-power ultrasound, pulse electric field). Food design is another important focus point for consumers’ sensory appeal and economic success of foods. Hence, technologies as 3D food printing can be particularly useful for manufacturing. Based on the above, presented topics are relevant to sustainable functional food production, functional fruit juices, BACs, “hurdle technology,” advanced food processing, 3D food printing, and authentic fruits

    Technology 2001: The Second National Technology Transfer Conference and Exposition, volume 2

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    Proceedings of the workshop are presented. The mission of the conference was to transfer advanced technologies developed by the Federal government, its contractors, and other high-tech organizations to U.S. industries for their use in developing new or improved products and processes. Volume two presents papers on the following topics: materials science, robotics, test and measurement, advanced manufacturing, artificial intelligence, biotechnology, electronics, and software engineering

    Autonomous Vehicles

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    This edited volume, Autonomous Vehicles, is a collection of reviewed and relevant research chapters, offering a comprehensive overview of recent developments in the field of vehicle autonomy. The book comprises nine chapters authored by various researchers and edited by an expert active in the field of study. All chapters are complete in itself but united under a common research study topic. This publication aims to provide a thorough overview of the latest research efforts by international authors, open new possible research paths for further novel developments, and to inspire the younger generations into pursuing relevant academic studies and professional careers within the autonomous vehicle field
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