Digital Commons Network^™

Impact Of Local Attenuation Approximations When Estimating Correlation Length From Backscattered Ultrasound Echoes, Timothy A. Bigelow, William D. O'Brien

Timothy A. Bigelow

Estimating the characteristic correlation length of tissue microstructure from the backscattered power spectrum could improve the diagnostic capability of medical ultrasound. Previously, size estimates were obtained after compensating for source focusing, the frequency-dependent attenuation along the propagation path (total attenuation), and the frequency-dependent attenuation in the scattering region (local attenuation). In this study, the impact of approximations of the local attenuation on the scatterer size estimate was determined using computer simulations and theoretical analysis. The simulations used Gaussian impedance distributions with an effective radius of 25 μm randomly positioned in a homogeneous half-space sonified by a spherically focused source (f/1 …

Simulations Of A New Continuous Steelmaking Process, Jorg Annie Peter, Kent D. Peaslee, D. G. C. Robertson

Materials Science and Engineering Faculty Research & Creative Works

A new continuous steelmaking process has been designed in an effort to reduce meltshop costs and increase productivity beyond the possibilities of current EAF-LMF-CC meltshops. This paper discusses possible operational performance based on industrially-verified kinetic, thermodynamic, and heat-transfer models. Dynamic simulations predict variations in steel chemistry and temperature, resulting from steel treatment and upsets. Savings in costs are projected because of increased metallic yield, lower energy requirements, more efficient use of deoxidants and alloys, fewer man-hours per ton, and decreased capital investment.

A Comparative Analysis Of Air-To-Ground Engagement Outcomes In The Joint Warfare System (Jwars) And The Jwars-Joint Semi-Automated Forces Federation, Melissa Anne St. Peter

Computational Modeling & Simulation Engineering Theses & Dissertations

Multi-resolution modeling is the process by which a single model is created by connecting multiple individual models to describe phenomena at different levels of resolution [1]. "When we change resolutions, replacing a detailed model by a more aggregate one, we must ask whether results are 'consistent'" [2].

There are many methods of determining if the results of two simulations are 'consistent'. However, they are very entailed and require a detailed understanding of the individual models including their functionality, algorithms, and inner workings. A straight forward and rapid way of assessing potential inconsistencies is through a statistical comparison of the model …

Modeling Of The Effects Of Athermal Flow Strength And Activation Energy For Dislocation Glide On The Nanoindentation Creep Of Nickel Thin Film At Room Temperature

A.S. Md Abdul Haseeb

Nanoindentation creep behaviour of nickel at room temperature has been modeled based on the obstacle-controlled dislocation glide mechanism. Using the model, the effects of two important materials parameters viz. the activation free energy required by dislocation to overcome an obstacle without any aid from external stress, ΔF and the athermal flow strength, τ0, which is the flow strength of solids at 0 K are systematically studied. It has been found that ΔF plays a dominant role in room temperature creep properties of nickel. The role of ΔF is particularly dominant in determining the time dependent deformation. On the other hand, …

Computational Modeling To Predict Mechanical Function Of Joints: Validations And Applications Of Lower Leg Simulations, Peter C. Liacouras

Theses and Dissertations

Computational models of musculoskeletal joints and limbs can provide useful information about joint mechanics. Validated models can be used as a predictive device for understanding joint function and serve as a clinical tool for predicting the outcome of surgical procedures. A new computational modeling approach was developed for simulating joint kinematics that are dictated by bone/joint anatomy, ligamentous constraints, and applied loading.Three-dimensional computational models of the lower leg were created. Model development involved generating three-dimensional surfaces from CT images, followed by importing these surfaces into SolidWorks and COSMOSMotion. ThroughSolidWorks and COSMOSMotion, each bone surface was created into a solid object …

Teaching Lean Manufacturing Concepts Using Physical Simulations Within Engineering Technology Program, Alok Verma

Engineering Technology Faculty Publications

Physical Simulations have a proven record as a teaching tool. Concepts that are often hard to grasp are made easy by the use of physical simulation activities. The constructivism learning theory suggests that people learn better by actively participating in the process of learning. Effectiveness of simulation-based learning is well recognized. According to the Encyclopedia of Educational Technology, "Simulation-based learning involves the placement of a student into a realistic scenario or situation. The student is then responsible for any changes that occur as a result of their decisions." The computer integrated manufacturing course in the mechanical engineering technology program was …

Modeling Of The Effects Of Athermal Flow Strength And Activation Energy For Dislocation Glide On The Nanoindentation Creep Of Nickel Thin Film At Room Temperature

A.S. Md Abdul Haseeb

Nanoindentation creep behaviour of nickel at room temperature has been modeled based on the obstacle-controlled dislocation glide mechanism. Using the model, the effects of two important materials parameters viz. the activation free energy required by dislocation to overcome an obstacle without any aid from external stress, ΔF and the athermal flow strength, τ0, which is the flow strength of solids at 0 K are systematically studied. It has been found that ΔF plays a dominant role in room temperature creep properties of nickel. The role of ΔF is particularly dominant in determining the time dependent deformation. On the other hand, …