15 research outputs found
04461 Abstracts Collection -- Practical Approaches to Multi-Objective Optimization
From 07.11.04 to 12.11.04, the Dagstuhl Seminar 04461
``Practical Approaches to Multi-Objective Optimization\u27\u27 was held
in the International Conference and Research Center (IBFI),
Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available
Dagstuhl News January - December 2006
"Dagstuhl News" is a publication edited especially for the members of the Foundation "Informatikzentrum Schloss Dagstuhl" to thank them for their support. The News give a summary of the scientific work being done in Dagstuhl. Each Dagstuhl Seminar is presented by a small abstract describing the contents and scientific highlights of the seminar as well as the perspectives or challenges of the research topic
Understanding Complexity in Multiobjective Optimization
This report documents the program and outcomes of the Dagstuhl Seminar 15031 Understanding Complexity in Multiobjective Optimization. This seminar carried on the series of four previous Dagstuhl Seminars (04461, 06501, 09041 and 12041) that were focused on Multiobjective Optimization, and strengthening the links between the Evolutionary Multiobjective Optimization (EMO) and Multiple Criteria Decision Making (MCDM) communities. The purpose of the seminar was to bring together researchers from the two communities to take part in a wide-ranging discussion about the different sources and impacts of complexity in multiobjective optimization. The outcome was a clarified viewpoint of complexity in the various facets of multiobjective optimization, leading to several research initiatives with innovative approaches for coping with complexity
Technology for large space systems: A bibliography with indexes (supplement 19)
This bibliography lists 526 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1988 and June 30, 1988. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems
Numerical modelling of bidirectional dry gas face seals
The optimization of the geometrical parameters of the aerodynamic lift features and the
analysis of the fluid flow in the seal interface are inter-twined. Any small changes in the
geometrical parameters of the aerodynamic lift features significantly affect the performance
of a non-contacting gas face seal.
For a gas face seal to function with optimum performance requires that the optimum
geometrical parameters be identified. This can be achieved through a lengthy trial and error
process, often heavily dependent on the designer’s depth of insight, itself dependent on
experience, or can be achieved through automated numerical methods.
The purpose of this research was to develop a reliable numerical model that can serve
as a design tool for simulating the performance of both unidirectional and bidirectional
dry gas face seals. This was achieved in three steps. The first approach consisted in
developing a 2D numerical model that employed the Reynolds equation for seals operating
at very low rotating speeds and low pressure differentials. In the second step a 3D-CFD
model was assembled and the practicability of using CFD, in a seal design loop, for seals
operating in wide range of operating conditions, was investigated. This model employed a
commercial CFD package (ANSYS CFX version 11). For last approach both models were
incorporated into an automatic optimization tool that can generate optimal seal geometries
with a minimum of human intervention.
An extensive set of results from the analysis of dry gas face seals spanning across different
operating conditions and geometrical seal face profiles, with the inclusion of convergent
radial taper, are presented and discussed in this thesis. The results obtained from the
Reynolds equation and 3D CFD models are compared and critically analysed. Results
obtained with both models are validated against test data obtained from AESSEAL plc,
the sponsor of this research. The 3D CFD model predictions showed a better agreement
with the test data on the seal leakage than the Reynolds equation model. The leakage rates
and fluid film thickness predictions illustrate how the 3D CFD model can be used for seal
design while overcoming some of the shortcomings of the Reynolds equation based models.
The major limitation of the 3D CFD model is that it is computationally expensive.
An automatic optimization tool which can be used for the design of dry gas face seals has
been presented. The improvements achieved from the optimization of a spiral groove face
seal utilising the automatic optimization tool are: 4.8% increase of opening force, 13.2%
reduction of seal leakage, 20.7% increase of design efficiency parameter, 28.3% increase of
axial film stiffness and 15.9% reduction of power consumption. A proposed new design of
dry gas face seal capable of bidirectional operation has been presented. This type of seal
outperformed the spiral groove face seal, in reverse rotation of the sealing shaft, in terms of
opening force and positive axial film stiffness
Bibliography of Lewis Research Center technical publications announced in 1993
This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1993. All the publications were announced in the 1993 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses
Climate-Smart Forestry in Mountain Regions
This open access book offers a cross-sectoral reference for both managers and scientists interested in climate-smart forestry, focusing on mountain regions. It provides a comprehensive analysis on forest issues, facilitating the implementation of climate objectives. This book includes structured summaries of each chapter. Funded by the EU’s Horizon 2020 programme, CLIMO has brought together scientists and experts in continental and regional focus assessments through a cross-sectoral approach, facilitating the implementation of climate objectives. CLIMO has provided scientific analysis on issues including criteria and indicators, growth dynamics, management prescriptions, long-term perspectives, monitoring technologies, economic impacts, and governance tools
Climate-Smart Forestry in Mountain Regions
This open access book offers a cross-sectoral reference for both managers and scientists interested in climate-smart forestry, focusing on mountain regions. It provides a comprehensive analysis on forest issues, facilitating the implementation of climate objectives. This book includes structured summaries of each chapter. Funded by the EU’s Horizon 2020 programme, CLIMO has brought together scientists and experts in continental and regional focus assessments through a cross-sectoral approach, facilitating the implementation of climate objectives. CLIMO has provided scientific analysis on issues including criteria and indicators, growth dynamics, management prescriptions, long-term perspectives, monitoring technologies, economic impacts, and governance tools
Aeronautical engineering: A cumulative index to a continuing bibliography (supplement 248)
This publication is a cumulative index to the abstracts contained in Supplements 236 through 247 of Aeronautical Engineering: A Continuing Bibliography. The bibliographic series is compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). Seven indexes are included -- subject, personal author, corporate source, foreign technology, contract number, report number and accession number