177,558 research outputs found
Preliminary aerothermal design of axial compressors
No full textThis dissertation documents a compressor preliminary design study conducted by the author
in fulfilment of his MSc thesis requirements. The compressor is intended for a new
development engine within the 20Klbf thrust category, planned to be used on a short-haul
aircraft, namely the ERJ-190.
A market research suggests that there exists a definite opportunity for a commercially
profitable engine within this thrust class. Furthermore, the proposed new engine is projected
to outperform current production engines on critical issues such as fuel efficiency and
operability.
By and large, the objectives of this work have been achieved and a compressor design and
layout is suggested, which matched or exceeded all the initial requirements. The quality of
the results from this study are thought to be of sufficient detail to allow a further, more
detailed development study to resolve some subtle pending issues. It is expected that, some
compressor stages may have to be altered slightly during detailed design to augment their
performance and ease of manufacture and assembly.
Throughout this study, the importance of the compressor design figure of merits, pertaining
to a short haul engine, has been outlined and their interaction on the design process is well
documented. Furthermore, some rather unorthodox objectives such as compressor
performance retention and reliability have been discussed. The author approached these
subjects in an innovative way due to the limited non-proprietary knowledge available on
these issues, especially considering their implications within preliminary design.
Furthermore, the author developed and tested a new preliminary turbomachinery design code,
named Turbodev, which can be used as an aid in future compressor design endeveours.
Turbodev can handle most types of compressor layouts and generates an overall aerodynamic
assessment of the turbomachinery performance.
In conclusion; this documentation and the associated literature review aim to provide the
reader with an overview of the work done and yield a better understanding of the decisions
that face any design bureau when developing a new or modified engine component.The research work disclosed in this publication is partially funded by the
Strategic Educational Pathways Scholarship Scheme (Malta). The
scholarship is part-financed by the European Union – European Social
Fund under Programme II – Cohesion Policy 2007-2013
Isolation and characterization of the cDNA for a Ciona intestinalis RNA binding protein: spatial and temporal expression during development
No full textIsolation and characterization of the cDNA for a Ciona intestinalis RNA binding protein: spatial and temporal expression during development
No full textIsolation and characterization of the cDNA for a Ciona intestinalis RNA binding protein: spazial and temporal expression during development.
No full textIsolation and characterization of the cDNA for a Ciona intestinalis RNA binding protein: spazial and temporal expression during development.
No full textIsolation and characterization of the cDNA for a Ciona intestinalis RNA binding protein:spatial and temporal expression during development
No full textParity without Equality
No full textJennifer M. Piscopo examines how the crisis of representation in Costa Rica has placed a ceiling on gender equality in representation. The restructuring of the Costa Rican party system and party fragmentation has made electing multiple candidates from any one ballot more difficult. Top spots have become even more prestigious and more likely to be allocated to men, which reduces women’s electoral chances. Corruption scandals, party breakdown, citizen frustration, and economic problems tainted the administration of the nation’s first female president, Laura Chinchilla. Female legislators have often worked to promote women’s issues and feminist policies, but Chinchilla eschewed feminism, even though several of her policies did benefit women. Overall, her failed presidency may create difficulties for other women seeking top political offices and could have negative consequences for views of women in politics. These challenges notwithstanding, Piscopo concludes that Costa Rica remains at the vanguard of women’s political representation in Latin America.</p
Incidence of wind spectrum and turbulence intensity on the design of mooring systems for floating offshore wind turbines
No full textThe paper focuses on the incidence of wind spectrum and turbulence intensity on the design of stationkeeping systems for Floating Offshore Wind Turbines. After a brief review about the employed nonlinear time-domain hydrodynamic model, some basics about the Ultimate and Fatigue Limit State design conditions of the mooring system are provided. Subsequently, the two wind spectra, employed in the numerical simulations, are briefly introduced. The former is the NPD wind spectrum, generally applied for the design of mooring systems for typical offshore structures, employed in the oil and gas sector. The latter is the Kaimal wind spectrum, generally employed for the design of offshore wind turbines in conjunction with different turbulence models, depending on the operative scenario. The numerical investigation is performed considering the DeepCwind platform, equipped with the 5 MW NREL wind turbine, as reference support structure, deployed in the North Sea area. Three different water depths, from 200 up to 400 m, are considered. It is verified that both the wind spectrum and turbulence model play a fundamental role not only for the optimum design of the stationkeeping system, but also for the proper selection of the line scope, as well as of the leading usage factors
Mooring design and selection for floating offshore wind turbines on intermediate and deep water depths
No full textThe paper focuses on design and selection of mooring systems for Floating Offshore Wind Turbines (FOWTs) for intermediate and deep water depths, based on ultimate, accidental and fatigue limit state design conditions, with reference to power production, parked wind turbine and mooring line fault conditions. Platform static and dynamic offsets are determined by a purposely developed 6DOF programme in the frequency domain, accounting for first and second order motions. The Dutch tri-floater platform, together with the well-known 5 MW NREL wind turbine, is assumed as reference design. Besides, two sites, the one in the Southern North Sea, near Dogger Bank on water depths ranging from 50 up to 80 m, the other one in the Northern North Sea, near the Troll field area on water depths ranging from 200 up to 350 m, are assumed as candidate deployment areas, to investigate the effect of: (i) line number, (ii) platform admissible offset and line scope, (iii) offshore/onshore planned maintenance inspections and (iv) mooring technology on relevant installation and maintenance costs. A preliminary cost analysis is also performed and some recommendations are given to correctly choice the most suitable mooring configuration, as a function of water depth
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
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