194 research outputs found
Thermal barrier coating life prediction model development
The objectives are to determine the predominant modes of degradation of a plasma sprayed thermal barrier coating system, and then to develop and verify life prediction models accounting for these degradation modes. Two possible predominant failure mechanisms being evaluated are bond coat oxidation and bond coat creep
Thermal barrier coating life prediction model
The objectives of this program are to determine the predominant modes of degradation of a plasma sprayed thermal barrier coating system, and then to develop and verify life prediction models accounting for these degradation modes. The program is divided into two phases, each consisting of several tasks. The work in Phase 1 is aimed at identifying the relative importance of the various failure modes, and developing and verifying life prediction model(s) for the predominant model for a thermal barrier coating system. Two possible predominant failure mechanisms being evaluated are bond coat oxidation and bond coat creep. The work in Phase 2 will develop design-capable, causal, life prediction models for thermomechanical and thermochemical failure modes, and for the exceptional conditions of foreign object damage and erosion
Detection of kinetic change points in piece-wise linear single molecule motion
Single-molecule approaches present a powerful way to obtain detailed kinetic information at the molecular level. However, the identification of small rate changes is often hindered by the considerable noise present in such single-molecule kinetic data. We present a general method to detect such kinetic change points in trajectories of motion of processive single molecules having Gaussian noise, with a minimum number of parameters and without the need of an assumed kinetic model beyond piece-wise linearity of motion. Kinetic change points are detected using a likelihood ratio test in which the probability of no change is compared to the probability of a change occurring, given the experimental noise. A predetermined confidence interval minimizes the occurrence of false detections. Applying the method recursively to all sub-regions of a single molecule trajectory ensures that all kinetic change points are located. The algorithm presented allows rigorous and quantitative determination of kinetic change points in noisy single molecule observations without the need for filtering or binning, which reduce temporal resolution and obscure dynamics. The statistical framework for the approach and implementation details are discussed. The detection power of the algorithm is assessed using simulations with both single kinetic changes and multiple kinetic changes that typically arise in observations of single-molecule DNA-replication reactions. Implementations of the algorithm are provided in ImageJ plugin format written in Java and in the Julia language for numeric computing, with accompanying Jupyter Notebooks to allow reproduction of the analysis presented here
Measurement of the permeability of tungsten to hydrogen and to oxygen Final report
Permeation rate measurements of hydrogen and oxygen through tungsten at elevated temperature
Measurement of the permeability of tungsten to nitrogen Final report
Permeation of nitrogen through arc-cast tungste
Phase-space finite element methods applied to the first-order form of the transport equation
The application of the finite element method to the first-order form of the neutron transport equation is reviewed. The general theoretical foundation of the finite element application is summarized, including a derivation of the weak form, a discussion of the treatment of all boundary conditions as natural boundary conditions and a few remarks concerning convergence. Results of the 1-D application are presented including a description of the discontinuous phase-space finite elements. The 2-D application is discussed and its application to the classic ray effect problem is examined. It is concluded that the finite element method does alleviate the ray effect but at the considerable expense of computational time and memory requirements. To address this concern, a new `segmentation' scheme for the 2-D application is described. This scheme yields satisfactory results for the ray effect problem while reducing the computational cost by nearly an order of magnitude. Finally a few remarks are presented concerning the time-dependent application and the paper concludes with some general comments concerning the overall application of the finite element method to the first-order equation and comparison with alternative methods.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24572/1/0000854.pd
Patenting and licensing of university research: promoting innovation or undermining academic values?
Since the 1980s in the US and the 1990s in Europe, patenting and licensing activities by universities have massively increased. This is strongly encouraged by governments throughout the Western world. Many regard academic patenting as essential to achieve 'knowledge transfer' from academia to industry. This trend has far-reaching consequences for access to the fruits of academic research and so the question arises whether the current policies are indeed promoting innovation or whether they are instead a symptom of a pro-intellectual property (IP) culture which is blind to adverse effects. Addressing this question requires both empirical analysis (how real is the link between academic patenting and licensing and 'development' of academic research by industry?) and normative assessment (which justifications are given for the current policies and to what extent do they threaten important academic values?). After illustrating the major rise of academic patenting and licensing in the US and Europe and commenting on the increasing trend of 'upstream' patenting and the focus on exclusive as opposed to non-exclusive licences, this paper will discuss five negative effects of these trends. Subsequently, the question as to why policymakers seem to ignore these adverse effects will be addressed. Finally, a number of proposals for improving university policies will be made
The hydrodynamic efficiency of laser-target acceleration
The acceleration of a thin foil using a laser pulse is studied. It is shown that the acceleration efficiency eta H is heavily dependent on the behaviour of the corona ejected by the foil: there is no universal relation eta H( Delta M/M0),M0 and Delta M being initial foil mass and ablated mass, respectively. Known results on the coronal flow are used to check the theory against experimental data available in the literature; effects due to both a non-planar corona, and the time-dependence of the laser irradiance, are considered. The agreement with experiments is substantially better than that for previous analyses. Acceleration of thin spherical shells is also discussed
Enhancing students’ motivation to learn software engineering programming techniques: a collaborative and social interaction approach
To motivate students to study advanced programming techniques, including the use of architectural styles such as the model–view–controller pattern, we have con-ducted action research upon a project based-learning approach. In addition to collabo-ration, the approach includes students’ searching and analysis of scientific documents and their involvement in communities of practice outside academia. In this paper, we report the findings of second action research cycle, which took place throughout the fourth semester of a six-semester program. As with the previous cycle during the pre-vious academic year, students did not satisfactorily achieve expected learning out-comes. More groups completed the assigned activities, but results continue to reflect poor engagement in the communities of practice and very low performance in other learning tasks. From the collected data we have identified new approaches and recom-mendations for subsequent research.Fundação para a Ciência e Tecnologia (FCT), Portugal, for Ph.D. Grants SFRH/BD/91309/2012 and SFRH/BD/87815/201
Teachers in an Interdisciplinary Learning Community: Engaging, Integrating, and Strengthening K-12 Education
This study examines the inputs (processes and strategies) and outputs (perceptions, skill development, classroom transfer, disciplinary integration, social networking, and community development) of a yearlong, interdisciplinary teacher learning and development experience. Eleven secondary math and science teachers partnered with an interdisciplinary team of university engineering mentors in a yearlong engineering education and project implementation program. It consisted of a 6-week on-site resident professional development and collaboration experience, with an ongoing support and follow-up including digital systems. Mixed-method, multisource data indicate that teachers engaged with motivations combining personal, intrinsic interest and classroom integration goals. They formed and sustained an active community of learning and practice that supported their success, on-site and through classroom integration, thereby promoting innovations. Teachers reported positive perceptions throughout the program and demonstrated significant, productive trajectories of change-over-time. Teachers learned and transferred task-specific engineering and scientific skills, as well as more general inquiry-based pedagogical strategies to their secondary classrooms.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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