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 80 for “"Zone Model"”.
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A Five-Zone Model for Direct Injection Diesel Combustion
… imaging studies have provided a new conceptual model of the internal structure of direct injection diesel fuel jets as well as empirical correlations predicting jet development and structure. This information was used to create a diesel cycle simulation model using C language including …
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Hardening Cohesive/Overlapping Zone Model and Fractal Approach to Ductile Fracture
… in substantial experiments. The cohesive zone model and fractal approach are the cornerstone in this thesis. It is essential that a proper fracture theory should basically take into both the stress intensification and material disorder at different scales into account. A Hardening …
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A multi-zone model of the CFR engine : investigating cascading autoignition and octane rating
The CFR engine is the standardised research engine used for the measurement of knock resistance of fuels through the Research Octane Number (RON) and Motor Octane Number(MON) tests. In standard production engines, knock manifests as an almost instantaneous pressure rise followed by knock ringing" …
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Study of natural ventilation design by integrating the multi-zone model with CFD simulation
… ventilation design. The integration of the multi-zone model and the computational fluid dynamics (CFD) simulation provides a way to assess the performance of natural ventilation in whole buildings, as well as the detailed thermal environmental information in some particular space. This work has …
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A simplified multi-zone model for determining the placement of bio-defense sensors in large buildings
… sensors in large facilities. A reduced-order model is developed that allows buildings to be subdivided into larger sections while maintaining a higher degree of accuracy than building analysis models with the same level of granularity. The problem is formulated as a network model with the …
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A novel discrete damage zone model and enhancement of the extended finite element method for fracture mechanics problems
… method (XFEM), and (II) a discrete damage zone model for quasi-static and fatigue delamination in composites. The first method improves XFEM when applied to general nonlinear materials when crack tip analytical solutions are not available. For linear elastic materials, Branch functions are …
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Car Following and Dynamic Dilemma Zone Model for Determining Gate Operation Times Based on Driver Behavior at Highway-Rail Intersections
… speed profiles are examined in the approach zone, stopping distance zone, and the track zone for single vehicles as well as platoons of vehicles. A simulation model incorporating the field data, determination of a dynamic dilemma zone, and algorithms to determine gate operation times is …
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Development of a novel hybrid field and zone fire model
… and implementation of a novel hybrid field/zone fire model, linking a fire field model to a zone model. This novel concept was implemented using SMARTFIRE (a fire field model produced at the University of Greenwich) and two different zone models (CFAST which is produced by NIST and FSEG-ZONE …
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The Ductile to Brittle Transition in Polycarbonate
<p>An advanced bulk constitutive model is used with a new cohesive zone model that is stress state and rate-dependent in order to simulate the ductile to brittle failure transition in polycarbonate. The cohesive zone model is motivated by experimental evidence that two different critical energies …
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An Improved Mathematical Model to Simulate the Stock in Pulse Fired Reheating Furnaces
The zone method of radiation analysis has been widely used in the steel industry to develop mathematical models to simulate the temperature performance of furnaces.<br/><br/>The zone method can provide an accurate calculation of the radiation exchanges, which are the main mode of heat transfer in …
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Dynamic Fracture of Adhesively Bonded Composite Structures Using Cohesive Zone Models
… an initial crack. A cohesive-decohesive zone model, similar to the cohesive zone model known in the fracture mechanics literature as the Dugdale-Barenblatt model, is adopted to represent the degradation of the material ahead of the crack tip. This model unifies strength-based crack …
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Modeling and characterizing bi-directional airflow in natural ventilation
… scenarios are simulated and analyzed: 1. Two-zone model with pure buoyancy forces, 2. Multi-zone model with combined wind and buoyancy forces. In the 1st model, a new concept of "local discharge coefficient" is proposed for its consistency under different boundary conditions. The influence of …
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One-Dimensional Performance Modeling of Centrifugal Flow Vaned Diffusers
The Two Element in Series (TEIS) and Two Zone models stand out as powerful tools that enable deeper understanding of compressor stage designs after they have been tested. The insights gained from these investigations have aided in improving new stage designs. Up to now, it has only been possible to …
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Stochastic analysis of dense nonaqueous phase liquid dissolution in naturally heterogeneous subsurface systems
… DNAPL saturation distribution in a source zone is derived, based on the previous research to describe the field-scale nonuniform residual DNAPL distribution. A local-scale dissolution model is generalized from the laboratory experimental results. Effective transport and dissolution …
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Flexible Pavement Rut Depth Modeling For Different Climate Zones
… study was to develop pavement rutting empirical models for different climate zones to predict pavement rutting on granular base based on LTPP data. Flexible pavements with granular base course were considered for this study. These models lead to better understanding of rutting phenomena and the …
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Analytical Modeling of the Mechanics of Nucleation and Growth of Cracks
… an initial crack. A cohesive-decohesive zone model, similar to the cohesive zone model known in fracture mechanics as Dugdale-Barenblatt model, is adopted to represent the degradation of the material ahead of the crack tip. This model unifies strength-based crack initiation and fracture …
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Subsurface transport of fertilizer-applied nitrogen on the eastern shore of Virginia
… groundwater impacted surface water. The computer model, PRZM (Pesticide Root Zone Model) was used to simulate the transportation of nitrogen through the soil column, past the crop root zone to groundwater. Then MOC (Method of Characterization), a groundwater model, was used to transport the …
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Effect of lining thermal inertia on small-scale compartment fire
… reading was studied using radiation network models. Previous theoretical studies were implemented to provide improved models appropriate to the more complex arrangements considered here. Modeling was used to assess the radiation error of different sizes of thermocouple in the hot layer …
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Methodology for Using a Non-Linear Parameter Estimation Technique for Reactive Multi-Component Solute Transport Modeling in Ground-Water Systems
For a numerical or analytical model to be useful it should be ensured that the model outcome matches the observations or field measurements during calibration. This process has been typically done by manual perturbation of the model input parameters. This research investigates a methodology for …
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