MULTISCALE CHARACTERIZATION OF ΑLPHA-BETA TITANIUM ALLOYS USING HIGH THROUGHPUT SPHERICAL INDENTATION TEST PROTOCOLS

Traditionally, new materials follow well stablished paths from their manufacturing beginnings to their final application. Development, evaluation, certification and deployment are some of the steps in these processes. However, some of these stages are characterized for very specialized protocols, resulting in prolonged timelines from beginning to end. The design process of materials can sometimes be defined as ambiguous due to the lack of fundamental knowledge at salient length-scales. This can be attributed to the absence of trustworthy testing methods that provide meaningful and reliable knowledge on the behavior of materials at length-scales over different orders of magnitude. In addition to this characteristic, cost and time efficiency are also crucial attributes in the materials design field, as large amounts of data covering wide ranges or parameters provide stronger bases for physics-based models that can reverse-engineer the whole process. The work presented here, evaluates spherical nano-indentation protocols as a high-throughput approach for the mechanically characterization of several α- and α/β titanium alloys at the grain-scale level. We start by the exploring the mechanical response of primary-α grains, and their dependence on the HCP lattice orientation and the corresponding grain chemical composition. Next, we move into the mechanical behavior of single grains in fully basket-weave titanium microstructures. By looking into the grain responses, a reduction on the multiple microstructural features in this type of morphologies is accomplished, leading to better statements of the influence of lath-microstructure and α-lath orientations on the indentation properties. This work is accompanied by a thorough microstructural characterization/quantification of the basket-weave morphology that is later subjected to a dimensionality reduction for a simplified understanding. And finally, we aim to bridge multiresolution indentation measurements form a bimodal titanium microstructure for the subsequent evaluation of composite theories in the prediction of the effective indentation yield.Ph.D

High Efficiency Angles-Only Space-Based Approaches for Geosynchronous Orbit Catalog Maintenance With Sparse Information

The thesis of this dissertation proposes a novel filter algorithm to improve tracking and catalog maintenance of uncooperative satellites and other Resident Space Objects (RSOs) in Geosynchronous Equatorial Orbit (GEO). Tracking can be supported by space-based tracking from observer satellites (OBSs). Practical limitations can lead to long time gaps between measurement updates when tracking RSOs from an OBS, which may induce a loss of fidelity or divergence of the estimation algorithm. The Extended Kalman filter (EKF) is commonly used for tracking RSOs but it diverges as a consequence of nonlinearity in the dynamics and nonlinearity in the optical measurements from OBSs. Both nonlinear- ities cause the underlying probability density (PDF) of the state vector to deviate from a Gaussian distribution, leading to divergence after measurement update. The Unscented Kalman filter (UKF) and the Gaussian Mixture Model filter (GMM) were proposed to solve the divergence problem in the EKF. A hybrid algorithm, the Hybrid Kalman-particle filter (HKF), was developed and likewise assessed to improve on the EKF methodology by com- bining with particle filtering techniques. Lastly, this work presents a novel filter algorithm, the Extended Step-Back Kalman filter (ESBKF), in which the measurement update is ap- plied at a time in the past when the distribution of the RSO in state-space is approximately Gaussian. The filter statistics are then propagated forward to the present, and the nonlinear effects of the dynamics are dramatically reduced, thereby avoiding divergence longer

Nineteen seventy two Venus flyby/entry probe mission study, book 2 Final technical report

Systems engineering and constraints, cost estimates, and program schedule for Venus flyby/entry probe missio

Parallel Manipulators

In recent years, parallel kinematics mechanisms have attracted a lot of attention from the academic and industrial communities due to potential applications not only as robot manipulators but also as machine tools. Generally, the criteria used to compare the performance of traditional serial robots and parallel robots are the workspace, the ratio between the payload and the robot mass, accuracy, and dynamic behaviour. In addition to the reduced coupling effect between joints, parallel robots bring the benefits of much higher payload-robot mass ratios, superior accuracy and greater stiffness; qualities which lead to better dynamic performance. The main drawback with parallel robots is the relatively small workspace. A great deal of research on parallel robots has been carried out worldwide, and a large number of parallel mechanism systems have been built for various applications, such as remote handling, machine tools, medical robots, simulators, micro-robots, and humanoid robots. This book opens a window to exceptional research and development work on parallel mechanisms contributed by authors from around the world. Through this window the reader can get a good view of current parallel robot research and applications

National Geodetic Satellite Program, Part 1

The work performed by individual contributors to the National Geodetic Satellite Program is presented. The purpose of the organization, the instruments used in obtaining the data, a description of the data itself, the theory used in processing the data, and evaluation of the results are detailed for the participating organizations

Factories of the Future

Engineering; Industrial engineering; Production engineerin

Social work with airports passengers

Social work at the airport is in to offer to passengers social services. The main methodological position is that people are under stress, which characterized by a particular set of characteristics in appearance and behavior. In such circumstances passenger attracts in his actions some attention. Only person whom he trusts can help him with the documents or psychologically

Factories of the Future

Engineering; Industrial engineering; Production engineerin