cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.7515356
title: A Numerical Study on Smart Material Selection for Flapped and Twisted Morphing Wing Configurations

description: ABSTRACT: The developments of innovative adaptive structures on Unmanned Aerial Vehicles (UAVs), such as morphing wings, can potentially reduce system complexities by eliminating control surfaces and their auxiliary equipment. This technology has the potential of allowing a UAV to adapt to different mission requirements or to execute a particular mission more effectively by maintaining an optimum airfoil section over a range of speeds for different segments of a mission profile. Studies on a number of smart materials candidates are currently available in the open literature to achieve wing morphing. The material selection depends on several factors including fast dynamic response, low weight, capability to operate over a wide range of flight conditions and low power consumption. This paper presents a review on smart materials technologies for UAV morphing wings. A numerical study in terms of power requirements is also presented for two morphing wing concepts: flapped and twisted wing planforms. The energy calculations for both morphing configurations were based on a two-step procedure. The first step consists of computing the aerodynamic energy using an in-house Vortex-Lattice (VL) based program. Subsequently the pressure field obtained from the first step is then mapped into a finite element mesh and the structural strain energy is calculated. The numerical results indicated that flapped morphing wings have a better aerodynamic performance when compared to twisted wings and different morphing levels can be achieved using lighter smart materials with lower specific energy for this configuration.
DOI: 10.6084/m9.figshare.7515356.v1
title: A Numerical Study on Smart Material Selection for Flapped and Twisted Morphing Wing Configurations

description: ABSTRACT: The developments of innovative adaptive structures on Unmanned Aerial Vehicles (UAVs), such as morphing wings, can potentially reduce system complexities by eliminating control surfaces and their auxiliary equipment. This technology has the potential of allowing a UAV to adapt to different mission requirements or to execute a particular mission more effectively by maintaining an optimum airfoil section over a range of speeds for different segments of a mission profile. Studies on a number of smart materials candidates are currently available in the open literature to achieve wing morphing. The material selection depends on several factors including fast dynamic response, low weight, capability to operate over a wide range of flight conditions and low power consumption. This paper presents a review on smart materials technologies for UAV morphing wings. A numerical study in terms of power requirements is also presented for two morphing wing concepts: flapped and twisted wing planforms. The energy calculations for both morphing configurations were based on a two-step procedure. The first step consists of computing the aerodynamic energy using an in-house Vortex-Lattice (VL) based program. Subsequently the pressure field obtained from the first step is then mapped into a finite element mesh and the structural strain energy is calculated. The numerical results indicated that flapped morphing wings have a better aerodynamic performance when compared to twisted wings and different morphing levels can be achieved using lighter smart materials with lower specific energy for this configuration.
DOI: 10.6084/m9.figshare.7510088
title: Extending the Student Qualitative Undertaking Involvement Risk Model

description: ABSTRACT: The Student Qualitative Undertaking Involvement Risk Model (SQUIRM) was designed to facilitate the determination of the impact of using student (or inexperienced) workers, on a project. The model identifies several prospective categories of risk. It, then, discusses the risk potential and source and provides a limited consideration of how to mitigate this risk. The risk sources considered included those specific to student (inexperienced worker) involvement, standard risks and standard risk sources which are enhanced by the use of student (inexperienced) workers. This paper presents a qualitative assessment framework and begins the process of quantifying the model. The difference between the use of students (in an academic or industrial setting) versus inexperienced workers is also considered. The base model is presented and extended by further tracing the risk sources back, using root cause analysis techniques. The application of the base and extended models to various projects is discussed. Considerations in choosing which model to use for a given application are also presented. The paper concludes by presenting a value model for considering student (inexperienced worker) involvement benefits versus associated risks, and the differences in the risk reward ratio between academic, internship and junior worker scenarios.
DOI: 10.6084/m9.figshare.7510088.v1
title: Extending the Student Qualitative Undertaking Involvement Risk Model

description: ABSTRACT: The Student Qualitative Undertaking Involvement Risk Model (SQUIRM) was designed to facilitate the determination of the impact of using student (or inexperienced) workers, on a project. The model identifies several prospective categories of risk. It, then, discusses the risk potential and source and provides a limited consideration of how to mitigate this risk. The risk sources considered included those specific to student (inexperienced worker) involvement, standard risks and standard risk sources which are enhanced by the use of student (inexperienced) workers. This paper presents a qualitative assessment framework and begins the process of quantifying the model. The difference between the use of students (in an academic or industrial setting) versus inexperienced workers is also considered. The base model is presented and extended by further tracing the risk sources back, using root cause analysis techniques. The application of the base and extended models to various projects is discussed. Considerations in choosing which model to use for a given application are also presented. The paper concludes by presenting a value model for considering student (inexperienced worker) involvement benefits versus associated risks, and the differences in the risk reward ratio between academic, internship and junior worker scenarios.
DOI: 10.6084/m9.figshare.7510598
title: Location Issues of Thin Shell Parts in the Reconfigurable Fixture for Trimming Operation

description: ABSTRACT: The location of thin shell parts is always a knotty problem during machining, welding, forming, assembling and inspection operations. This paper mainly focuses on the special location issues in the digital and flexible trimming process for aircraft skins fastened by reconfigurable fixture. Firstly, in view of the dynamic change of effective locators, the "X-2-1" location principle was proposed with reference to the "3-2-1" and "N-2-1" location schemes. Secondly, the standard procedure for solving location parameters was summarized in consideration of location admissibility, holding posture, locator layout and so on. Thirdly, a locating experiment was conducted to investigate the positional accuracy of the reconfigurable fixture and the calculation accuracy of location parameters solution. Fourthly, a quantitative evaluation method to evaluate the dynamic stiffness of the fixturing system was put forward. Moreover, the effects of location layout on the dynamic stiffness were analyzed using the finite element simulation system for the trimming process. A noticeable appearance had been observed that the cliff effect of the dynamic stiffness of the flexible fixturing system may be induced due to the dynamic change of effective locators. Finally, some conclusions and discussion on future works were given.
DOI: 10.6084/m9.figshare.7510598.v1
title: Location Issues of Thin Shell Parts in the Reconfigurable Fixture for Trimming Operation

description: ABSTRACT: The location of thin shell parts is always a knotty problem during machining, welding, forming, assembling and inspection operations. This paper mainly focuses on the special location issues in the digital and flexible trimming process for aircraft skins fastened by reconfigurable fixture. Firstly, in view of the dynamic change of effective locators, the "X-2-1" location principle was proposed with reference to the "3-2-1" and "N-2-1" location schemes. Secondly, the standard procedure for solving location parameters was summarized in consideration of location admissibility, holding posture, locator layout and so on. Thirdly, a locating experiment was conducted to investigate the positional accuracy of the reconfigurable fixture and the calculation accuracy of location parameters solution. Fourthly, a quantitative evaluation method to evaluate the dynamic stiffness of the fixturing system was put forward. Moreover, the effects of location layout on the dynamic stiffness were analyzed using the finite element simulation system for the trimming process. A noticeable appearance had been observed that the cliff effect of the dynamic stiffness of the flexible fixturing system may be induced due to the dynamic change of effective locators. Finally, some conclusions and discussion on future works were given.
DOI: 10.6084/m9.figshare.7515509
title: FSM-Based Test Case Generation Methods Applied to Test the Communication Software on Board the ITASAT University Satellite: A Case Study

description: ABSTRACT: The software in satellite applications has become increasingly larger, more complex and more integrated, so its verification and validation require exploration of new approaches. In this paper we present a Model-Based Testing (MBT) approach applied to the Communication Module of the ITASAT-1 university satellite. The models are Finite State Machines (FSM) representing the software behavior. In order to manage the difficulties to model the software behavior the approach employs the Conformance and Fault Injection (CoFI) testing methodology associated with the JPlavisFSM tool in the real context of a satellite's critical software. The former advises the modularization of the modelling into different types of behavior into different FSMs, while the latter integrates several FSM-based methods to derive test cases, provides facilities to design and to check properties of the models and computes metrics. The main result of this case study was the evaluation of the drawbacks on the design of the testing models supported by CoFI and JPlavisFSM. The models, test sets, metrics with the application of our approach applied to the Communication Module are presented. The paper discusses the benefits as well as the points requiring new researches.
DOI: 10.6084/m9.figshare.7515509.v1
title: FSM-Based Test Case Generation Methods Applied to Test the Communication Software on Board the ITASAT University Satellite: A Case Study

description: ABSTRACT: The software in satellite applications has become increasingly larger, more complex and more integrated, so its verification and validation require exploration of new approaches. In this paper we present a Model-Based Testing (MBT) approach applied to the Communication Module of the ITASAT-1 university satellite. The models are Finite State Machines (FSM) representing the software behavior. In order to manage the difficulties to model the software behavior the approach employs the Conformance and Fault Injection (CoFI) testing methodology associated with the JPlavisFSM tool in the real context of a satellite's critical software. The former advises the modularization of the modelling into different types of behavior into different FSMs, while the latter integrates several FSM-based methods to derive test cases, provides facilities to design and to check properties of the models and computes metrics. The main result of this case study was the evaluation of the drawbacks on the design of the testing models supported by CoFI and JPlavisFSM. The models, test sets, metrics with the application of our approach applied to the Communication Module are presented. The paper discusses the benefits as well as the points requiring new researches.
DOI: 10.6084/m9.figshare.7514696
title: Experimental Investigation of a Monopropellant Thruster Using Nitrous Oxide

description: ABSTRACT: Nitrous oxide is a monopropellant with potential for use in propulsion systems for orbit correction, positioning and attitude control of satellites. This paper presents experimental results with a 2N thruster prototype employing nitrous oxide gas decomposed by a rhodium oxide catalyst supported on alumina. Initially, the thruster design, the test bench and test procedures are described. Then the main experimental results, including thrust curves, mass flow rates, pressures and temperatures along the thruster are presented for pulsed operation. At the end specific impulses, characteristic velocities and thruster efficiencies are determined, thus indicating a catalytic decomposition efficiency of about 88%.
DOI: 10.6084/m9.figshare.7514696.v1
title: Experimental Investigation of a Monopropellant Thruster Using Nitrous Oxide

description: ABSTRACT: Nitrous oxide is a monopropellant with potential for use in propulsion systems for orbit correction, positioning and attitude control of satellites. This paper presents experimental results with a 2N thruster prototype employing nitrous oxide gas decomposed by a rhodium oxide catalyst supported on alumina. Initially, the thruster design, the test bench and test procedures are described. Then the main experimental results, including thrust curves, mass flow rates, pressures and temperatures along the thruster are presented for pulsed operation. At the end specific impulses, characteristic velocities and thruster efficiencies are determined, thus indicating a catalytic decomposition efficiency of about 88%.
DOI: 10.6084/m9.figshare.7515971.v1
title: The Open Innovation Journey in Emerging Economies: An Analysis of the Brazilian Aerospace Industry

description: ABSTRACT: Open innovation is the systematic integration of collaborative, sourcing and revealing practices into a firm's business strategy. Its implementation does not happen at once, but through a journey. This paper investigates this subject in an emergent economy context, the Brazilian aerospace industry, presenting the critical analysis of a questionnaire-based survey performed by means of personal in-company interviews in 22 firms. It comprises a wide range of practices associated with open innovation, connected to a conceptual model. We find open innovation elements in the sample, with no open business strategy behind them, though. Deficiencies regarding funding, R&D maturity and intellectual property protection prevent the cluster from being fully open innovator. Nevertheless, the culture company in the sample is very prone towards openness. From that, we conclude that open innovation in the cluster is still "unfreezing", but with great potential to emerge, once these problems are solved.
DOI: 10.6084/m9.figshare.7515971
title: The Open Innovation Journey in Emerging Economies: An Analysis of the Brazilian Aerospace Industry

description: ABSTRACT: Open innovation is the systematic integration of collaborative, sourcing and revealing practices into a firm's business strategy. Its implementation does not happen at once, but through a journey. This paper investigates this subject in an emergent economy context, the Brazilian aerospace industry, presenting the critical analysis of a questionnaire-based survey performed by means of personal in-company interviews in 22 firms. It comprises a wide range of practices associated with open innovation, connected to a conceptual model. We find open innovation elements in the sample, with no open business strategy behind them, though. Deficiencies regarding funding, R&D maturity and intellectual property protection prevent the cluster from being fully open innovator. Nevertheless, the culture company in the sample is very prone towards openness. From that, we conclude that open innovation in the cluster is still "unfreezing", but with great potential to emerge, once these problems are solved.
DOI: 10.6084/m9.figshare.7509614.v1
title: Development Status of L75: A Brazilian Liquid Propellant Rocket Engine

description: ABSTRACT: This paper provides an overview of the design and development process of the L75 Liquid Propellant Rocket Engine (LPRE). Being developed at Instituto de Aeronáutica e Espaço (IAE), it is the first Brazilian open-cycle liquid rocket engine pressurized by turbopump, designed to deliver 75 kN of thrust in vacuum as a cryogenic upper stage engine using liquid oxygen and ethanol. The Preliminary Design Review (PDR) was accomplished in December 2011 and December 2012 the project received from Agência Espacial Brasileira (AEB) a financial support, through an agreement with Fundação de Desenvolvimento da Pesquisa (FUNDEP), to proceeding with the development of models and tests. The main components of the engine, briefly described here, are thrust chamber assembly, gas generator, turbopump assembly, control system and ignition system.
DOI: 10.6084/m9.figshare.7509614
title: Development Status of L75: A Brazilian Liquid Propellant Rocket Engine

description: ABSTRACT: This paper provides an overview of the design and development process of the L75 Liquid Propellant Rocket Engine (LPRE). Being developed at Instituto de Aeronáutica e Espaço (IAE), it is the first Brazilian open-cycle liquid rocket engine pressurized by turbopump, designed to deliver 75 kN of thrust in vacuum as a cryogenic upper stage engine using liquid oxygen and ethanol. The Preliminary Design Review (PDR) was accomplished in December 2011 and December 2012 the project received from Agência Espacial Brasileira (AEB) a financial support, through an agreement with Fundação de Desenvolvimento da Pesquisa (FUNDEP), to proceeding with the development of models and tests. The main components of the engine, briefly described here, are thrust chamber assembly, gas generator, turbopump assembly, control system and ignition system.
DOI: 10.5517/ccdc.csd.cc26wxlm
title: CCDC 2052621: Experimental Crystal Structure Determination

description: Related Article: Ping-Ping Sun, Yi-Ming Li, Yu-Hang Zhang, Hongwei Shi, Fa-Nian Shi|2021|Inorg.Chim.Acta|521|120337|doi:10.1016/j.ica.2021.120337
DOI: 10.6084/m9.figshare.7511402.v1
title: Evaluation of Chemical Equilibrium and Non-Equilibrium Properties for LOX/LH2 Reaction Schemes

description: ABSTRACT: Nine chemical reaction models for equilibrium schemes and six chemical models for non-equilibrium ones are studied, considering different conditions found in real liquid oxygen/liquid hydrogen rocket engines. Comparisons between two eight-species models have shown that the most complex is the best one. Besides, it was also verified that the most complex model has been the fastest, among six- and eight-species models. Both combustion temperature and thermochemical/transport properties depend only on the chemical species considered by the used model. Comparisons among results from the implemented code (Gibbs 1.3), Chemical Equilibrium with Applications and Thermochemical Information and Equilibrium Calculations, these last two codes from NASA, have shown that Gibbs 1.3 evaluates correctly both combustion temperature and thermochemical properties. Furthermore, analyses have shown that mass generation rates are very dependent on third body reaction equations and forward reaction constants.
DOI: 10.6084/m9.figshare.7511402
title: Evaluation of Chemical Equilibrium and Non-Equilibrium Properties for LOX/LH2 Reaction Schemes

description: ABSTRACT: Nine chemical reaction models for equilibrium schemes and six chemical models for non-equilibrium ones are studied, considering different conditions found in real liquid oxygen/liquid hydrogen rocket engines. Comparisons between two eight-species models have shown that the most complex is the best one. Besides, it was also verified that the most complex model has been the fastest, among six- and eight-species models. Both combustion temperature and thermochemical/transport properties depend only on the chemical species considered by the used model. Comparisons among results from the implemented code (Gibbs 1.3), Chemical Equilibrium with Applications and Thermochemical Information and Equilibrium Calculations, these last two codes from NASA, have shown that Gibbs 1.3 evaluates correctly both combustion temperature and thermochemical properties. Furthermore, analyses have shown that mass generation rates are very dependent on third body reaction equations and forward reaction constants.
DOI: 10.6084/m9.figshare.7515098
title: Nanoelectronic Devices Based on Carbon Nanotubes

description: ABSTRACT: Carbon nanotubes are possible building blocks in the development of new generation of electronic devices. The carbon nanotubes allow one fabrication of devices using nanometric scales. They can be used in projects of a wide range of electronic and optoelectronic components such as diodes, transistors and interconnection elements, among others. This paper presents the state-of-the-art of this area, emphasizing the influence of quantum effects on the characteristics of such components.
DOI: 10.6084/m9.figshare.7515098.v1
title: Nanoelectronic Devices Based on Carbon Nanotubes

description: ABSTRACT: Carbon nanotubes are possible building blocks in the development of new generation of electronic devices. The carbon nanotubes allow one fabrication of devices using nanometric scales. They can be used in projects of a wide range of electronic and optoelectronic components such as diodes, transistors and interconnection elements, among others. This paper presents the state-of-the-art of this area, emphasizing the influence of quantum effects on the characteristics of such components.
DOI: 10.6084/m9.figshare.7510010
title: Gas Turbine Course's Teaching Process at Instituto Tecnológico de Aeronáutica: Theory and Laboratory

description: ABSTRACT: The Instituto Tecnológico de Aeronáutica (ITA) is an Engineering school maintained by the Air Force Command, Ministry of Defense. The aim of the Turbomachines Department at ITA is the human resources training for design and development of aeronautical and industrial gas turbines, necessary for the Gas Turbine Program of the Departamento de Ciência e Tecnologia Aeroespacial (DCTA). The human resources training is carried out in undergraduate and graduate courses at ITA, where topics in gas turbine and turbomachinery are taught. The gas turbine topic is taught in the undergraduate degree, in Mechanical-Aeronautical Engineering course, and focuses on gas turbines' performance for different configurations (turboshaft, turbojet and turbofan). Lecture notes containing the essential elements of the course are made available for the students, addressing the basic theory of the gas turbines required for the performance study at the design and off-design point. The technological aspects are presented and discussed during detailed studies of the actual cycle. Simple gas turbines and more sophisticated ones are studied, for both aeronautical and industrial application. Performance calculations at design and off-design point of the main engine's components and the cycle are done manually, encouraging students to develop spreadsheets. The theory is complemented with laboratory classes and technical visits, when the practicalities involving gas turbines operation and tests are presented to the students. As an activity laboratory class, the students perform disassembly-assembly of a small industrial gas turbine.