6,374 research outputs found
On the nature of the fragment environment created by the range destruction or random failure of solid rocket motor casings
Given here are predictions of fragment velocities and azimuths resulting from the Space Transportation System Solid Rocket Motor range destruct, or random failure occurring at any time during the 120 seconds of Solid Rocket Motor burn. Results obtained using the analytical methods described showed good agreement between predictions and observations for two specific events. It was shown that these methods have good potential for use in predicting the fragmentation process of a number of generically similar casing systems. It was concluded that coupled Eulerian-Lagrangian calculational methods of the type described here provide a powerful tool for predicting Solid Rocket Motor response
Centaur in-tank explosion flow fields within STS and Titan 4 payload spaces
Explosions are examined which result from the mixing of liquid hydrogen and liquid oxygen (LH2-LO2) such that the reactants are confined by the missile (CBM) body. Explosion which were confined by the ground surface (CBGS) were also studied, with results reported elsewhere. Initial attempts to predict the reported PYRO experimental results were unsuccessful. A new reaction energy addition hypothesis was then developed and tested. The results obtained provide reasonable agreement with the experiments both in the near and far field. Calculations were performed to predict the environment which would occur at the Galileo Radioisotope Thermoelectric Generator (RTG) location given a Centaur G' upper stage and an STS launch vehicle. It was concluded that the principle threat to the RTG in this environment would be the impact of a slug of LH2. No analyses were conducted to assess the response of the Galileo RTG to such an environment. It was shown that the flow field resulting from the failure of the Centaur G' tankage was benign. It was concluded that while the cryogen particle velocity was very high, the flow field density was extremely low. As a result, the dynamic pressure was a trivial eight psia
Summary of miscellaneous hazard environments for hypothetical Space Shuttle and Titan IV launch abort accidents
The various analyses described here were aimed at obtaining a more comprehensive understanding and definition of the environments in the vicinity of the Radioisotope Thermal Generator (RTG) during certain Space Transportation System (STS) and Titan IV launch abort accidents. Addressed here are a number of issues covering explosion environments and General Purpose Heat Source Radioisotope Thermoelectric Generator (GPHS-RTG) responses to those environments
Validating adequacy and suitability of business-IT alignment criteria in an inter-enterprise maturity model
Aligning requirements of a business with its information technology is currently a major issue in enterprise computing. Existing literature indicates important criteria to judge the level of alignment between business and IT within a single enterprise. However, identifying such criteria in an inter-enterprise setting – or re-thinking the existing ones – is hardly addressed at all. Business-IT alignment in such settings poses new challenges, as in inter-enterprise collaborations, alignment is driven by economic processes instead of centralized decision-making processes. In our research, we develop a maturity model for business-IT alignment in inter-enterprise settings that takes this difference into account. In this paper, we report on a multi-method approach we devised to confront the validation of the business-IT alignment criteria that we included in the maturity model. As independent feedback is critical for our validation, we used a focus group session and a case study as instruments to take the first step in validating the business-IT alignment criteria. We present how we applied our approach, what we learnt, and what the implications were for our model
Investigation of thermodynamic mechanisms for the production of compounds essential for the origin of life First quarter technical report, Oct. 1 - Dec. 31, 1965
Expected thermodynamic equilibrium composition calculated for atmospheres of Earth, Venus, Mars, and Jupite
Correlating Architecture Maturity and Enterprise Systems Usage Maturity to Improve Business/IT Alignment
This paper compares concepts of maturity models in the areas of Enterprise Architecture and Enterprise Systems Usage. We investigate whether these concepts correlate, overlap and explain each other. The two maturity models are applied in a case study. We conclude that although it is possible to fully relate constructs from both kinds of models, having a mature architecture function in a company does not imply a high Enterprise Systems Usage maturity
Guided Interaction Exploration in Artifact-centric Process Models
Artifact-centric process models aim to describe complex processes as a
collection of interacting artifacts. Recent development in process mining allow
for the discovery of such models. However, the focus is often on the
representation of the individual artifacts rather than their interactions.
Based on event data we can automatically discover composite state machines
representing artifact-centric processes. Moreover, we provide ways of
visualizing and quantifying interactions among different artifacts. For
example, we are able to highlight strongly correlated behaviours in different
artifacts. The approach has been fully implemented as a ProM plug-in; the CSM
Miner provides an interactive artifact-centric process discovery tool focussing
on interactions. The approach has been evaluated using real life data sets,
including the personal loan and overdraft process of a Dutch financial
institution.Comment: 10 pages, 4 figures, to be published in proceedings of the 19th IEEE
Conference on Business Informatics, CBI 201
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