Rapid Contingency Simulation Modeling of the NASA Crew Launch Vehicle

The NASA Crew Launch Vehicle is a two-stage orbital launcher designed to meet NASA's current as well as future needs for human space flight. In order to free the designers to explore more possibilities during the design phase, a need exists for the ability to quickly perform simulation on both the baseline vehicle as well as the vehicle after proposed changes due to mission planning, vehicle configuration and avionics changes, proposed new guidance and control algorithms, and any other contingencies the designers may wish to consider. Further, after the vehicle is designed and built, the need will remain for such analysis in the event of future mission planning. An easily reconfigurable, modular, nonlinear six-degree-of-freedom simulation matching NASA Marshall's in-house high-fidelity simulator is created with the ability to quickly perform simulation and analysis of the Crew Launch Vehicle throughout the entire launch profile. Simulation results are presented and discussed, and an example comparison fly-off between two candidate controllers is presented

A Cryogenic Fluid System Simulation in Support of Integrated Systems Health Management

Simulations serve as important tools throughout the design and operation of engineering systems. In the context of sys-tems health management, simulations serve many uses. For one, the underlying physical models can be used by model-based health management tools to develop diagnostic and prognostic models. These simulations should incorporate both nominal and faulty behavior with the ability to inject various faults into the system. Such simulations can there-fore be used for operator training, for both nominal and faulty situations, as well as for developing and prototyping health management algorithms. In this paper, we describe a methodology for building such simulations. We discuss the design decisions and tools used to build a simulation of a cryogenic fluid test bed, and how it serves as a core technology for systems health management development and maturation

Online monitoring system using reactor and mass spectrometry

The combination of micro reactor and analytical devices are popular in research and industry, in addition to the automation of analytical tasks. An automated system for online reaction monitoring in a micro reactor using a mass spectrometer has therefore been realized. The system offers fast data acquisition at discrete time-point in a reaction process. In addition, different functions and utilities that facilitate the convenience to users are included: A dilution module, integration of the micro reactor system to an ICP-MS, two sampling methods, a heating module and a control software

Wireless Cyber-Physical Simulator and Case Studies on Structural Control

Abstract: Wireless Structural Control (WSC) systems can play a crucial role in protecting civil infrastructure in the event of earthquakes and other natural disasters. Such systems represent an exemplary class of cyber-physical systems that perform close-loop control using wireless sensor networks. Existing WSC research usually employs wireless sensors installed on small lab structures, which cannot capture realistic delays and data loss in wireless sensor networks deployed on large civil structures. The lack of realistic tools that capture both the cyber (wireless) and physical (structural) aspects of WSC systems has been a hurdle for cyber-physical systems research for civil infrastructure. This advances the state of the art through the following contributions. First, we developed the Wireless Cyber-Physical Simulator (WCPS), an integrated environment that combines realistic simulations of both wireless sensor networks and structures. WCPS integrates Simulink and TOSSIM, a state-of-the-art sensor network simulator featuring a realistic wireless model seeded by signal traces. Second, we performed two realistic case studies each combining a structural model with wireless traces collected from real-world environments. The building study combines a benchmark building model and wireless traces collected from a multi-story building. The bridge study combines the structural model of the Cape Girardea

Analysis for Hybrid Rocket Fuel Regression Using Stereolithographic Geometry

Hybrid Rocket Engines (HRE) have characteristically low fuel regression that limits their performance. Additive manufacturing and rapid prototyping can possibly solve some of the problems with Hybrid propulsion regression by creating geometry not possible with conventional manufacturing. This work is attempting to make geometric regression simulation of HRE easier by using STereoLithography (STL files) as the geometry. This analysis sets flow conditions, boundary conditions, propellant selection, and allows for fuel geometry to be altered to simulate geometry’s effects on regression rate and propellant performance. This model can be used for more advanced geometric analysis to improve and predict performance

Laplace-domain analysis of fluid line networks with applications to time-domain simulation and system parameter identification.

Networks of closed conduits containing pressurised fluid flow occur in many different instances throughout the natural and man made world. The dynamics of such networks are dependent not only on the complex interactions between the fluid body and the conduit material within each fluid line, but also on the coupling between different lines as they influence each other through their common junctions. The forward modelling (time-domain simulation), and inverse modelling (system parameter identification) of such systems is of great interest to many different research fields. An alternative approach to time-domain descriptions of fluid line networks is the Laplace-domain representation of these systems. A long standing limitation of these methods is that the frameworks for constructing Laplace-domain models have not been suitable for pipeline networks of an arbitrary topology. The objective of this thesis is to fundamentally extend the existing theory for Laplace-domain descriptions of hydraulic networks and explore the applications of this theory to forward and inverse modelling. The extensions are undertaken by the use of graph theory concepts to construct network admittance matrices based on the Laplace-domain solutions of the fundamental pipeline dynamics. This framework is extended to incorporate a very broad class of hydraulic elements. Through the use of the numerical inverse Laplace transform, the proposed theory forms the basis for an accurate and computationally efficient hydraulic network time-domain simulation methodology. The compact analytic nature of the network admittance matrix representation facilitates the development of two successful and statistically based parameter identification methodologies, one based on an oblique filtering approach combined with maximum likelihood estimation, and the other based on the expectation-maximisation algorithm.Thesis (Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 201

In-Situ Surface Science Studies of the Interaction between Sulfur Dioxide and Two-Dimensional Palladium Loaded-Cerium/Zirconium mixed Metal Oxide Model Catalysts

Cerium and zirconium oxides are important materials in industrial catalysis. Particularly, the great advances attained in the past 30 years in controlling levels of gaseous pollutants released from internal combustion engines can be attributed to the development of catalysts employing these materials. Unfortunately, oxides of sulfur are known threats to the longevity of many catalytic systems by irreversibly interacting with catalytic materials over some time period. In this work, polycrystalline cerium-zirconium mixed-metal-oxide (MMO) solid solutions of various molar ratios were synthesized. High resolution x-ray photoelectron spectroscopy (XPS) was used to characterize the model system. The spectral data was examined for revelation of the surface species that form on these metal oxides after insitu exposures to sulfur dioxide at various temperatures. The model catalysts were exposed to sulfur dioxide using a custom modified in-situ reaction cell. A reliable sample platen heater was designed and built to allow the exposure of the model system at temperatures up to 673 K. The results of this study demonstrate the formation of sulfate and sulfite adsorbed sulfur species. Temperature and compositional dependencies were displayed, with higher temperatures and ceria molar ratios displaying a larger propensity for forming surface sulfur species. In addition to analysis of sulfur photoemission, the photoemission regions of oxygen, zirconium, and cerium were examined for the materials used in this study before and after the aforementioned treatments with sulfur dioxide. The presence of surface hydroxyl groups was observed and metal oxidation state changes were probed to further enhance the understanding of sulfur dioxide adsorption on the synthesized materials. Palladium loaded mixed-metal oxides were synthesized using a unique solid-state methodology to probe the effect of palladium addition on sulfur dioxide adsorption. Microscopic characterization of the wafers made using palladium-loaded MMO materials provide justification for using this material preparation method in surface science studies. The addition of palladium to this model system is shown to have a strong effect on the magnitude of adsorption for sulfur dioxide on some material/exposure condition combinations. Ceria/zirconia sulfite and sulfate species are identified on the palladium-loaded MMO materials with adsorption sites located on the exposed oxide sites

Workflow repository for providing configurable workflow in ERP

Workflow pada ERP dengan domain fungsi yang besar rentan dengan adanya duplikasi. Membuat workflow repository yang menyimpan berbagai macam workflow dari proses bisnis ERP yang dapat digunakan untuk menyusun workflow baru sesuai kebutuhan tenant baru Metode yang diusulkan: Metode yang diusulkan terdiri dari 2 tahapan, preprocessing dan processing. Tahap preprocessing bertujuan untuk mencari common dan sub variant dari existing workflow variant. Workflow variant yang disimpan oleh pengguna adalah Procure to Pay workflow. Variasi tersebut diseleksi berdasarkan kemiripannya dengan similarity filtering, kemudian dimerge untuk mencari common dan sub variantnya. Common dan sub variant disimpan menggunakan metadata yang dipetakan pada basis data relasional. Deteksi common dan sub variant workflow mencapai tingkat akurasi sebesar 92%. Ccommon workflow terdiri dari 3-common dari 8-variant workflow. Common workflow tersebut memiliki tingkat kompleksitas lebih rendah 10% dari model sebelumnya. Tahapan processing adalah tahapan penyediaan configurable workflow. Pengguna memasukan query model untuk mencari workflow yang diinginkan. Dengan menggunakan metode similarity filtering, didapatkan common dan/atau sub variant yang memungkinkan. Pengguna dapat menggunakan common workflow melalui workflow designer untuk melakukan rekomposisi ulang. Penyediaan configurable workflow oleh ERP mencapai tingkat 100% dimana apapun yang diinginkan pengguna dapat disediakaan workflownya oleh ERP, ataupun sebagai dasar membentuk workflow yang lain. Berdasarkan hasil percobaan, tempat penyimpanan workflow dapat dibangun dengan arsitektur yang diajukan dan mampu menyimpan dan menyediakan workflow. Tempat penyimpanan ERP mampu mendeteksi workflow yang bersifat common dan sub variant. Tempat penyimpanan ERP mampu menyediakan configurable workflow, dimana pengguna dapat memanfaatkan common dan sub variant workflow untuk menjadi dasar mengkomposisi workflow yang lain. =================================================================================================== Workflow in ERP which covered big domain faced duplication issues. Scope of this research was developing workflow from business process ERP which could be used for required workflow as user needs. Proposed approach consisted of 2 stages preprocessing and processing. Preprocessing stages aimed for finding common and variant of sub workflow based on existing workflow variant. The workflow variants that were stored by user were procured to pay workflow. The workflows was filtered by similarity filtering method then merged for identifying the common and variant of sub workflow. The common and sub variant workflow were stored using metadata that mapped into relational database. The common and variant of sub workflow detection achieved 92% accuracy. The common workflow consisted of 3- the common workflow from 8-variant workflow. The common workflow has 10% lesser complexity than its predecessor. Processing was providing configurable workflow. User inputted query model to find required workflow. Utilizing similarity filtering, possible the common and variant of sub workflow was collected. User used the common workflow through workflow designer to recompose. Providing configurable workflow ERP achieved 100%, where any user need would be provided by ERP, as workflow or as based template for creating other. Based on evaluation, repository was built based on proposed architecture and was able to store or provide workflow. Repository detected workflow whether common or variant of sub workflow. Repository ERP was able to provide configurable ERP, where user utilized common and variant of sub workflow as based for creating one of their need

Deep Learning-Based Wave Digital Modeling of Rate-Dependent Hysteretic Nonlinearities for Virtual Analog Applications

Electromagnetic components greatly contribute to the peculiar timbre of analog audio gear. Indeed, distortion effects due to the nonlinear behavior of magnetic materials are known to play an important role in enriching the harmonic content of an audio signal. However, despite the abundant research that has been devoted to the characterization of nonlinearities in the context of virtual analog modeling over the years, the discrete-time simulation of circuits exhibiting rate-dependent hysteretic phenomena remains an open challenge. In this article, we present a novel data-driven approach for the wave digital modeling of rate-dependent hysteresis using recurrent neural networks (RNNs). Thanks to the modularity of wave digital filters, we are able to locally characterize the wave scattering relations of a hysteretic reluctance by encapsulating an RNN-based model into a single one-port wave digital block. Hence, we successfully apply the proposed methodology to the emulation of the output stage of a vacuum-tube guitar amplifier featuring a nonlinear transformer