The coating thickness profiles for EB-PVD TBCs deposited on stationary cylinders have been experimentally measured and theoretically modeled using Knudsen's cosine law of emissions {1}. A comparison of the experim...
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The coating thickness profiles for EB-PVD TBCs deposited on stationary cylinders have been experimentally measured and theoretically modeled using Knudsen's cosine law of emissions {1}. A comparison of the experimental results with the model reveals that the model needs to be modified to account for the sticking coefficient as well as a ricochet factor. These results are also discussed in terms of the effects of substrate temperature on the sticking coefficient, the ricochet factor, and coating density.
The microstructures of EB-PVD TBC's have been characterized as a function of angular position and cylinder height on stationary cylindrical surfaces in the coating chamber. The microstructures were evaluated using...
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The microstructures of EB-PVD TBC's have been characterized as a function of angular position and cylinder height on stationary cylindrical surfaces in the coating chamber. The microstructures were evaluated using x-ray diffraction for qualitative crystallographic texture as well as by optical microscopy and scanning electron microscopy for crystal column growth morphology. The results revealed several very strong crystallographic textures as well as a variety of crystal growth morphology.
Many engineering students enter and exit general chemistry courses with little appreciation of chemistry's relevance to other fields. At WPI many of these students go on to take introductory materials science and ...
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Many engineering students enter and exit general chemistry courses with little appreciation of chemistry's relevance to other fields. At WPI many of these students go on to take introductory materials science and arrive with poor attitudes about chemistry and little retention of key concepts, but then become more engaged as they discover connections to engineering applications. Consequently, instructors in chemistry and mechanical engineering collaborated to augment general chemistry laboratories with explicit "bridges" to material properties and applications. Evaluation results showed that while students' attitudes toward chemistry were unaffected by bridging, particular aspects of the students' lab experience were enhanced to a statistically significant degree. Similar cross-disciplinary collaborations might be considered elsewhere as a means of helping students find meaning and integrate subject matter, in a manner that is more feasible than large-scale course or curriculum restructuring.
This panel will present three different models of international engineering opportunities. Each of these universities - Boston University, University of Rhode Island and worcesterpolytechnicinstitute - has developed...
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This panel will present three different models of international engineering opportunities. Each of these universities - Boston University, University of Rhode Island and worcesterpolytechnicinstitute - has developed international opportunities for undergraduate engineers that work within their respective curricula and offer an enhanced education to students who take advantage of the opportunities offered. This session will provide an understanding of the management and logistical structure of each program, and how it fits into the respective curricula. Returned students from each of the programs will be present as well.
This panel presents three different models of international engineering opportunities. Each of these universities-Boston University, University of Rhode Island and worcesterpolytechnicinstitute-has developed interna...
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This panel presents three different models of international engineering opportunities. Each of these universities-Boston University, University of Rhode Island and worcesterpolytechnicinstitute-has developed international opportunities for undergraduate engineers that work within their respective curricula and offer an enhanced education to students who take advantage of the opportunities offered. This session provides an understanding of the management and logistical structure of each program, and how it fits into the respective curricula.
A new quenching characterization measurement system has been developed to experimentally determine the temperature versus time data for selected steel alloys in mineral and vegetable oils. The main features of the que...
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A new quenching characterization measurement system has been developed to experimentally determine the temperature versus time data for selected steel alloys in mineral and vegetable oils. The main features of the quenching characterization system are the data acquisition system, the data analysis hardware and software and the probe. The probe can be fabricated from the specific alloy being considered. The steel probe allows the characterization of the steel-quenchant system. The analysis of the quenching data can provide cooling rates as well as heat transfer coefficients that may be used for further analysis of a quenched component. The results and analysis of data from AISI 4140 quenched in mineral oils are presented and discussed.
A unified framework for the study of stability of solutions to delay differential equations perturbed deterministically and stochastically has been presented. We review the concepts of Hopf bifurcation, centre manifol...
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A unified framework for the study of stability of solutions to delay differential equations perturbed deterministically and stochastically has been presented. We review the concepts of Hopf bifurcation, centre manifold, integral averaging method and pth-moment Lyapunov exponent, and then demonstrate their role in the stability study of a modified Duffing oscillator with time delay. Sufficient conditions ensuring D- and p-bifurcations and the changes in character of the probability density function are established for fixed and positive time delay.
Periodic solutions of delay differential equations (DDEs) splitting into stable and unstable branches are examined in an infinite-dimensional space for fixed and multiple time delays. The center manifold theorem and t...
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Periodic solutions of delay differential equations (DDEs) splitting into stable and unstable branches are examined in an infinite-dimensional space for fixed and multiple time delays. The center manifold theorem and the classical Hopf bifurcation theorem for the study of periodic solutions of ordinary differential equations (ODEs) are employed to reduce the infinite-dimensional character of the DDEs to finite-dimensional ODEs. Using integral averaging method, the vector field of the ODEs is converted and averaged into amplitude a and phase φ relations. From these relations bifurcation equations of the form ℑ (a, φ) = 0 for the solution branches are derived.
We present a two degrees of freedom model of machining dynamics that compactly captures the nonlinear effects of regeneration, tool wear and plowing under orthogonal machining. Extensive simulation experiments show th...
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We present a two degrees of freedom model of machining dynamics that compactly captures the nonlinear effects of regeneration, tool wear and plowing under orthogonal machining. Extensive simulation experiments show that the solutions to the governing equations of the model bear distinct similarities to signals from our earlier experiments, as reflected by both visual state portraits as well as the values of the quantifiers of a steady state dynamic system. Governing equations of the model lead to nonlinear delay differential equations, which we reduce to ordinary differential equations using Hopf bifurcation theorem and centre manifold theorem. Despite the ongoing efforts by the authors of this paper to quantify the simulations results analytically and experimentally, we strongly believe that our proposed model will be found to be amenable for studying and analyzing bifurcations that can lead to chatter in machining.
A large deflection elasticity model was used to describe the tensile elastic modulus of cartilage tissues during three point bending tests. Native and engineered cartilage were compared for both auricular and costal c...
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ISBN:
(纸本)0780367170
A large deflection elasticity model was used to describe the tensile elastic modulus of cartilage tissues during three point bending tests. Native and engineered cartilage were compared for both auricular and costal cartilage types.
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