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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

Development of a CubeSat Conceptual Design Tool and Implementation of the EPS Design Module

Nogrady, Sean K 01 June 2021 (has links) (PDF)
This thesis is the product of an effort to develop a CubeSat Conceptual Design Tool for the California Polytechnic State University CubeSat Laboratory. Such a tool is necessary due to inefficiencies with the current conceptual design process. It is being developed to increase accessibility, reduce design time, and promote good systems engineering within CubeSat development. The development of the architecture of a conceptual design tool, the core user-interface element, and the completion of a module for the electrical power subsystem is the focus of this thesis. The architecture is built around different modules to design different subsystems that work in conjunction. The module in the tool was developed to allow a user to size an electrical power subsystem, and that is the basis for future subsystem development. Model-based Systems Engineering was also utilized as an endpoint for the tool’s outputs, and a CubeSat Model has been built for this effort. Validation has been successful on the Conceptual Design Tool as implemented at this time, so the tool it is ready to design CubeSat electrical power subsystems and be expanded upon by other tool developers.
292

Comparison and Design of Simplified General Perturbation Models (SGP4) and Code for NASA Johnson Space Center, Orbital Debris Program Office

Miura, Nicholas Z 01 May 2009 (has links) (PDF)
This graduate project compares legacy simplified general perturbation model (SGP4) code developed by NASA Johnson Space Center, Orbital Debris Program Office, to a recent public release of SGP4 code by David Vallado. The legacy code is a subroutine in a larger program named PREDICT, which is used to predict the location of orbital debris in GEO. Direct comparison of the codes showed that the new code yields better results for GEO objects, which are more accurate by orders of magnitude (error in meters rather than kilometers). The public release of SGP4 also provides effective results for LEO and MEO objects on a short time scale. The public release code was debugged and modified to provide instant functionality to the Orbital Debris Program Office. Code is provided in an appendix to this paper along with an accompanying CD. A User’s Guide is presented in Chapter 7.
293

Picasso Interface for Horizon Simulation Framework

Kirkpatrick, Brian E 01 August 2010 (has links) (PDF)
The Horizon Simulation Framework, or HSF, is a modeling and simulation framework compiled from C/C++ source code into a command line program. Picasso is an interface designed to control the input files to Horizon by providing visual tools to create and manipulate the XML files used to define an HSF system of assets, their environment, and other simulation parameters. Picasso also supports the visualization of Horizon output in several different forms, and import mechanics from online space object catalogues.
294

The Multidisciplinary Design Optimization of a Distributed Propulsion Blended-Wing-Body Aircraft

Ko, Yan-Yee Andy 29 April 2003 (has links)
The purpose of this study is to examine the multidisciplinary design optimization (MDO) of a distributed propulsion blended-wing-body (BWB) aircraft. The BWB is a hybrid shape resembling a flying wing, placing the payload in the inboard sections of the wing. The distributed propulsion concept involves replacing a small number of large engines with many smaller engines. The distributed propulsion concept considered here ducts part of the engine exhaust to exit out along the trailing edge of the wing. The distributed propulsion concept affects almost every aspect of the BWB design. Methods to model these effects and integrate them into an MDO framework were developed. The most important effect modeled is the impact on the propulsive efficiency. There has been conjecture that there will be an increase in propulsive efficiency when there is blowing out of the trailing edge of a wing. A mathematical formulation was derived to explain this. The formulation showed that the jet "fills in" the wake behind the body, improving the overall aerodynamic/propulsion system, resulting in an increased propulsive efficiency. The distributed propulsion concept also replaces the conventional elevons with a vectored thrust system for longitudinal control. An extension of Spence's Jet Flap theory was developed to estimate the effects of this vectored thrust system on the aircraft longitudinal control. It was found to provide a reasonable estimate of the control capability of the aircraft. An MDO framework was developed, integrating all the distributed propulsion effects modeled. Using a gradient based optimization algorithm, the distributed propulsion BWB aircraft was optimized and compared with a similarly optimized conventional BWB design. Both designs are for an 800 passenger, 0.85 cruise Mach number and 7000 nmi mission. The MDO results found that the distributed propulsion BWB aircraft has a 4% takeoff gross weight and a 2% fuel weight. Both designs have similar planform shapes, although the planform area of the distributed propulsion BWB design is 10% smaller. Through parametric studies, it was also found that the aircraft was most sensitive to the amount of savings in propulsive efficiency and the weight of the ducts used to divert the engine exhaust. / Ph. D.
295

Clean Wing Airframe Noise Modeling for Multidisciplinary Design and Optimization

Hosder, Serhat 13 September 2004 (has links)
A new noise metric has been developed that may be used for optimization problems involving aerodynamic noise from a clean wing. The modeling approach uses a classical trailing edge noise theory as the starting point. The final form of the noise metric includes characteristic velocity and length scales that are obtained from three-dimensional, steady, RANS simulations with a two- equation k-omega turbulence model. The noise metric is not the absolute value of the noise intensity, but an accurate relative noise measure as shown in the validation studies. One of the unique features of the new noise metric is the modeling of the length scale, which is directly related to the turbulent structure of the flow at the trailing edge. The proposed noise metric model has been formulated so that it can capture the effect of different design variables on the clean wing airframe noise such as the aircraft speed, lift coefficient, and wing geometry. It can also capture three-dimensional effects which become important at high lift coefficients, since the characteristic velocity and the length scales are allowed to vary along the span of the wing. Noise metric validation was performed with seven test cases that were selected from a two-dimensional NACA 0012 experimental database. The agreement between the experiment and the predictions obtained with the new noise metric was very good at various speeds, angles of attack, and Reynolds Number, which showed that the noise metric is capable of capturing the variations in the trailing edge noise as a relative noise measure when different flow conditions and parameters are changed. Parametric studies were performed to investigate the effect of different design variables on the noise metric. Two-dimensional parametric studies were done using two symmetric NACA four-digit airfoils (NACA 0012 and NACA 0009) and two supercritical (SC(2)-0710 and SC(2)-0714) airfoils. The three-dimensional studies were performed with two versions of a conventional transport wing at realistic approach conditions. The twist distribution of the baseline wing was changed to obtain a modified wing which was used to investigate the effect of the twist on the trailing edge noise. An example study with NACA 0012 and NACA 0009 airfoils demonstrated a reduction in the trailing edge noise by decreasing the thickness ratio and the lift coefficient, while increasing the chord length to keep the same lift at a constant speed. Both two- and three-dimensional studies demonstrated that the trailing edge noise remains almost constant at low lift coefficients and gets larger at higher lift values. The increase in the noise metric can be dramatic when there is separation on the wing. Three-dimensional effects observed in the wing cases indicate the importance of calculating the noise metric with a characteristic velocity and length scale that vary along the span. The twist change does not have a significant effect on the noise at low lift coefficients, however it may give significant noise reduction at higher lift values. The results obtained in this study show the importance of the lift coefficient on the airframe noise of a clean wing and favors having a larger wing area to reduce the lift coefficient for minimizing the noise. The results also point to the fact that the noise reduction studies should be performed in a multidisciplinary design and optimization framework, since many of the parameters that change the trailing edge noise also affect the other aircraft design requirements. It's hoped that the noise metric developed here can aid in such multidisciplinary design and optimization studies. / Ph. D.
296

The Role of Constraints and Vehicle Concepts in Transport Design: A Comparison of Cantilever and Strut-Braced Wing Airplane Concepts

Ko, Yan-Yee Andy 15 May 2000 (has links)
The purpose of this study is to examine the multidisciplinary design optimization (MDO) of a strut-braced wing (SBW) aircraft compared to similarly designed cantilever wing aircraft. In this study, four different configurations are examined: cantilever wing aircraft, fuselage mounted engine SBW, wing mounted engine SBW, and wingtip mounted engine SBW. The cantilever wing design is used as a baseline for comparison. Two mission profiles were used. The first called for a 7380 nmi range with a 305 passenger load based on a typical Boeing 777 mission. The second profile was supplied by Lockheed Martin Aeronautical Systems (LMAS) and has a 7500 nmi range with a 325 passenger load. Both profiles have a 0.85 cruise Mach number and a 500 nmi reserve range. Several significant refinements and improvements have been made to the previously developed MDO code for this study. Improvements included using ADIFOR (Automatic Differentiation for FORTRAN) to explicitly compute gradients in the design code. Another major change to the MDO code is the improvement of the optimization architecture to allow for a more robust optimization process. During the Virginia Tech SBW study, Lockheed Martin Aeronautical Systems (LMAS) was tasked by NASA Langley to evaluate the results of previous SBW studies. During this time, the original weight equations which were obtained from NASA Langley's Flight Optimization System (FLOPS) was replaced by LMAS proprietary equations. A detailed study on the impact of the equations from LMAS on the four designs was done, comparing them to the designs that used the FLOPS equations. Results showed that there was little difference in the designs obtained using the new equations. An investigation of the effect of the design constraints on the different configurations was performed. It was found that in all the design configurations, the aircraft range proved to be the most crucial constraint in the design. However, results showed that all three SBW designs were less sensitive to constraints than the cantilever wing aircraft. Finally, a double-deck fuselage concept was considered. A double deck fuselage configuration would result in a greater wing/strut intersection angle which would, in turn, reduce interference drag at that section. Due to the lack of available data on double deck fuselage aircraft, a detailed study of passenger and cargo layout was done. Optimized design showed that there was a small improvement in takeoff gross weight and fuel weight over the single-deck fuselage SBW results when compared with a similarly designed cantilever wing aircraft. / Master of Science
297

Multidisciplinary Design Optimization of a Strut-Braced Wing Aircraft

Grasmeyer, Joel M. III 07 May 1998 (has links)
The objective of this study is to use Multidisciplinary Design Optimization (MDO) to investigate the use of truss-braced wing concepts in concert with other advanced technologies to obtain a significant improvement in the performance of transonic transport aircraft. The truss topology introduces several opportunities. A higher aspect ratio and decreased wing thickness can be achieved without an increase in wing weight relative to a cantilever wing. The reduction in thickness allows the wing sweep to be reduced without incurring a transonic wave drag penalty. The reduced wing sweep allows a larger percentage of the wing area to achieve natural laminar flow. Additionally, tip-mounted engines can be used to reduce the induced drag. The MDO approach helps the designer achieve the best technology integration by making optimum trades between competing physical effects in the design space. To perform this study, a suite of approximate analysis tools was assembled into a complete, conceptual-level MDO code. A typical mission profile of the Boeing 777-200IGW was chosen as the design mission profile. This transport carries 305 passengers in mixed class seating at a cruise Mach number of 0.85 over a range of 7,380 nmi. Several single-strut configurations were optimized for minimum takeoff gross weight, using eighteen design variables and seven constraints. The best single-strut configuration shows a 15% savings in takeoff gross weight, 29% savings in fuel weight, 28% increase in L/D, and a 41% increase in seat-miles per gallon relative to a comparable cantilever wing configuration. In addition to the MDO work, we have proposed some innovative, unconventional arch-braced and ellipse-braced concepts. A plastic solid model of one of the novel configurations was created using the I-DEAS solid modeling software and rapid prototyping hardware. / Master of Science
298

[pt] HOMENS AUTORES DE VIOLÊNCIA DOMÉSTICA E FAMILIAR CONTRA MULHER NA CIDADE DE MANAUS NO CONTEXTO DA LEI MARIA DA PENHA / [en] MALE PERPETRATORS OF DOMESTIC AND FAMILY VIOLENCE AGAINST WOMEN IN MANAUS CITY IN THE CONTEXT OF THE MARIA DA PENHA LAW

NEREYDA CARDOSO MUNIZ DE OLIVEIRA SANTOS 05 January 2012 (has links)
[pt] O presente estudo partiu do questionamento: Como os programas de atendimento a mulher que sofreu violência doméstica e familiar em Manaus-AM tem incluído os homens autores dessa violência, HAV, em seus serviços. A Lei 11.340-2006, reconhecida como Lei Maria da Penha prevê em seus artigos 35 e 45 serviços de atendimento aos HAV em centros de educação e reabilitação e ou programas de recuperação e reeducação,por considerar a importância de ser oferecida uma assistência resolutiva a todos os envolvidos na dinâmica da violência acometida. Assim, para alcançar resposta a indagação feita, foi desenvolvida uma pesquisa exploratória de natureza qualitativa, junto aos profissionais que atuam em dois programas públicos de atenção a mulher acometida de violência doméstica, visando conhecer como se dá a aplicabilidade da Lei em relação aos HAV, para além de sua responsabilização pelos atos cometidos. Os depoimentos obtidos revelam a inexistência de ações que atinjam nesse sentido, especialmente os HAV, na esfera governamental, embora os profissionais ouvidos nas entrevistas semi-estruturadas realizadas considerem de real necessidade a implementação de medidas preventivas e assistenciais voltadas para os homens no enfrentamento da violação dos direitos das mulheres no meio doméstico. Eles compreendem a complexidade da situação de violência vivenciada pela mulher, identificam os obstáculos e a precariedade de recursos disponíveis para se efetivar o acompanhamento de todos os envolvidos no âmbito da violência doméstica. Apontam também algumas iniciativas nessa direção. A aplicabilidade integral da Lei Maria da Penha ainda tem um longo caminho para ser realidade. / [en] This study began with the questioning: How care programs that women who suffered domestic and famile violence in Manaus-AM has included men perpetrators of this violence, HAV in their services. Law 11.340-2006, known as the Maria da Penha Law provides in Articles 35 and 45 care services to HAV in centers of education and rehabilitation and or recovery and rehabilitation programs, considering the importance of being offered a problem-solving assistance to all those involved in the dynamics of violence affected. Thus, the quest to achieve response was developed made an exploratory qualitative research, the professionals who work in two programs of public attention to women suffering from domestic violence, to determine how is the applicability of the Act in relation to HAV for beyond its responsibility for the acts committed. The statements obtained show the absence of actions to achieve this effect, especially HAV, in the governmental sphere, although the professionals heard in the semi-structured interviews of real need to consider the implementation of preventive measures and assistance aimed at men in dealing with violation women s rights in captivity. They understand the complexity of the situation of violence experienced by women, identifying the obstacles and limited resources available to effect the monitoring of all those involved in domestic violence. Also suggest some initiatives in this direction. The full applicability of the Maria da Penha Law still has a long way to reality.
299

Evaluation of camshaft control strategies for a GCI engine using a multidisciplinary optimisation framework

Kianifar, Mohammed R., Campean, Felician, Richardson, D. January 2014 (has links)
No / This paper presents a calibration optimization study for a Gasoline Direct Injection engine based on a multidisciplinary design optimization (MDO) framework. The paper presents the experimental framework used for the GDI engine mapping, followed by an analysis of the calibration optimization problem. The merits of the MDO approach to calibration optimization are discussed in comparison with a conventional two-stage approach based on local trade-off optimization analysis, focused on a representative emissions drive cycle (NEDC) and limited part load engine operation. The benefits from using the MDO optimisation framework are further illustrated with a study of relative effectiveness of different camshaft timing control strategies (twin independent Versus fixed timing, exhaust only, inlet only and fixed overlap / dual equal) for the reference GDI engine based on the part load test data. The main conclusion is that the MDO structure offers an effective framework for the GDI steady state calibration optimization analysis.
300

Adherence to Treatment Advice in Patients with Heart Failure : Connections to mental health, social and socioeconomic factors

Lassbo Lundquist, Moa January 2024 (has links)
Aim: The aim of this study is to examine adherence among patients with HF and its potential association with mental health, social support and socioeconomic status.  Introduction: For patients with heart failure, self-care is strongly advised, encompassing prescribed medication intake, fluid reduction and weight control to maintain stability. Adherence is defined as the extent to which an individual's behaviour aligns with recommendations concerning prescribed medications, lifestyle advice and specific treatment guidelines. Patients with adequate adherence exhibit better quality of life, reduced need for hospitalization and increased survival rates.  Methods: A descriptive cross-sectional study conducted at a University Hospital in Sweden 2021. An electronic questionnaire was used for data collection. The survey comprises four validated questionnaires: EHFScBS-9, BDI-II, KCCQ and HET. The collected data was summarized using descriptive statistics and data analysis was conducted using SPSS software. Results: A total of 479 individuals responded to the questionnaire. Adherence is defined as scoring 70 points or more on the EHFScB-9 scale and non-adherence as less than 70 points. 74% exhibited a score below 70. Experiencing a lack of information concerning heart condition was statistically significant in the non-adherence group. Depression was not significant but was more prevalent among non-adherent participants.  Conclusion: Non-adherence is widespread among patients with HF. Lack of information regarding heart failure was correlated with non-adherence. The study clearly highlights the potential for improvement in the advisory role of healthcare professionals to increase adherence.

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