Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 353 for “"Airflow"”.
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Airflow limitation in croup
… collapse of the trachea contributes much less to airflow obstruction than the subglottic swelling itself. The hypothesis investigated in this thesis is that air flow becomes restricted due to wave speed limitation. According to the theory of wave speed limitation, an increase in driving pressure …
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Directional Airflow for HVAC Systems
Directional airflow has been utilized to enable targeted air conditioning in cars and airplanes for many years, where the occupants could adjust the direction of flow. In the building sector however, HVAC systems are usually equipped with stationary diffusors that can only supply the air either in …
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Airflow dynamics in transverse dune interdunes
… the collection of geomorphologically relevant airflow data for four relatively simple transverse dune interdunes. The study locations were chosen in order to sample interdunes with different size and surface type characteristics, the dynamics of which were investigated for when incident flow …
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RESISTANCE OF BULK CANOLA OILSEED TO AIRFLOW
… or central spout. The resistance of canola to airflow and the effect of variety, moisture content, method of fill, direction of airflow and the amount and size of foreign material on the airflow resistance was determined using a laboratory apparatus. A mathematical model incorporating the …
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Airflow Analysis in Mechanically Ventilated Obstructed Rooms
It was concluded that for typical room flowrates and inlet types the room air distribution system is obstruction ratio independent. Local velocities and standard deviations varied with each obstruction setup and inlet combination. However, average air velocities and turbulence intensities were not …
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New turbulence models for indoor airflow simulation
… applied to predict different types of indoor airflows. The corresponding DNS or experimental data were used to validate the models. This study concludes that the two-layer models can predict airflows most accurately, better than many k -E models. The computing cost is significantly lower than …
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Modeling buoyancy-driven airflow in ventilation shafts
… used to simulate naturally ventilated buildings, airflow network tools (AFNs) are most commonly used for annual simulations. These AFNs, however, assume minimal momentum within each zone, which is a reasonable approximation in large atria, but is inappropriate in smaller ventilation shafts. This …
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Effectiveness and performance of double-skin airflow facades
Double-skin airflow facades have been in use for several years in European countries. They have yet to be used in the United States. One factor is that there is a lack of a heat transfer model which can accurately predict facade performance. A model of performance has been developed by Daniel …
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Laboratory simulation of subsurface airflow beneath a building
… some combination of the two results in increased airflow into the building. Additional research is needed for both experiments in order to obtain statistically significant results and resolve remaining uncertainties. Specific research needs include an improved wind source, additional monitoring …
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Simulation of Airflow and Heat Transfer in Buildings
Energy usage in buildings has become a major topic of research in the past decade, driven by the increased cost of energy. Designing buildings to use less energy has become more important, and the ability to analyze buildings before construction can save money in design changes. Computational fluid …
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Modeling and characterizing bi-directional airflow in natural ventilation
Bi-directional airflow in natural ventilation is an essential but not-well-understood scenario due to the complexity of airflow patterns as well as the strong coupling effect between temperature and ventilation. Neglecting bi-directional natural ventilation will result in problematic solutions and …
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Airflow in Interior Spaces: Implications on Comfort and Health
… community in Bhuj, the impacts of operational airflow changes are quantified with a focus on next-day thermal comfort. Applicable outside of India, the techniques can be used concurrently with active cooling systems to reduce energy consumption or extend capacity. Targeting near-term …
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Support vs. Steady Airflow: The Effect of Two Different Instructions on Subglottal Pressure, Sound Pressure Level, and Airflow Rate during Singing and Speaking
… (subglottal pressure, sound pressure level, and airflow rate) were obtained by using the KayPENTAX Phonatory Aerodynamic System. Three instructions were given in randomized order to 49 participants: (A) Sing the way you usually sing (baseline); (B) Allow your breath to flow steadily with the …
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CFD simulation of the airflow through the human respiratory tract
… lower airways by carrying out simulations of the airflow through the human respiratory tract. Three geometries, consisting of the ETA, CT-derived lower airway, and a combination of the two were utilized in simulations that were performed for transient breathing in addition to constant …
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POMA : a zonal model for airflow and temperature distribution analysis
… is a new kind of numerical model to simulate the airflow and temperature distribution within a room by means of personal computers. It is an intermediate model between multizone and Computational Fluid Dynamics (CFD) model. Compared to multizone models, zonal models can provide engineers with an …
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Study of airflow and thermal stratification in naturally ventilated rooms
… in the space, based on a few critical room airflow and physical parameters. Developing such criteria required conducting a thorough study of the physics of turbulent jets and plumes, their development in room-sized enclosures, and their effect on the airflow and heat transfer dynamics in a …
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A mesoscale study of frontal airflow, moisture, and cumulus convection.
Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Meteorology.
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Airflow sensing with arrays of hydrogel supported artificial hair cells
… also increases in a linear fashion with applied airflow pressure (3.39 pA/m s??). Array sensing tests show that the bilayers' consistent spectral responses allow for an accurate localization of the airflow source. However, temporal variations in bilayer size affect sensitivity properties and make …
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Optimising the airflow performance of ventilators for natural ventilation in buildings.
… air-tight so that ventilation is confined to airflow through intentionally provided openings only. These purpose-provided openings typically consist of one or a combination of basic components such as louvers, insect-screens or noise baffles. An extensive literature review indicated that the …
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Numerical investigation of airflow and aerosol deposition characteristics within human airways
… is used for the numerical investigation of the airflow and the aerosol deposition characteristics within the upper human airways. LES is performed using the Eulerian-Lagrangian framework where the airflow is modeled using the Eulerian formulation, and the aerosol evolution is tracked in a …
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