Dissertations / Theses on the topic 'Cargo flights'

The diploma thesis describes performance in the area of air transport, based on performance of national economies of two selected neighbouring countries, Czech Republic and Germany, through comparison of their gross domestic product in the selected time period. The operating performance is focused mainly on transportation performance of air transport. First part of the thesis is dealing with interconnection of economy with air transportation. Crucial part of the work contains analysis of development of GDP and analysis of development of transportation performance of both countries. Part of the thesis is also acquisition of passenger-kilometre data derived from fuel consumption and produced emissions of CO2.

By measuring the time of flight of scattered x-ray photons, the point of interaction, assuming a single scatter, can be determined, providing a three dimensional image of cargo containers. The present work introduces the technique, and provides experimental and theoretical results to show the feasibility of such a technique. Monte Carlo simulations were performed to investigate the proportion of multiple scatter detected using a proposed experimental setup, and it was found that it accounted for almost 50% of the recorded signal. Monte Carlo simulations of a scintillation detector were provided and used to design the detectors used. Experimental measurements at a picosecond length x-ray source resulted in the reconstruction of scatter position of photons interacting in a 5 cm thick test object to an accuracy of 12 cm full width at half maximum. Preliminary experiments were also performed using a conventional commercially available linear accelerator with a pulse length of 170 ns. Deconvolution techniques were applied to the recorded data to estimate the position of scatter. An analytic single scatter forward model was derived from the radiative transfer equation, discretised and the inverse problem was solved using a number of different methods. The alternating direction method of multipliers was adapted for nonlinear problems and provided image quality that was comparable to the gold standard linear method.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada
The measurement result is complete only if it contains the measurand and its units, uncertainty and coverage factor. The uncertainty estimation for the parameters acquired by the FTI is a known process. To execute this task the Institute of Research and Flight Test (IPEV) developed the SALEV© system which is fully compliant with the applicable standards. But the measurement set also includes Derived Parameters. The uncertainty evaluation of these parameters can be solved by cumbersome partial derivates. The search for a simpler solution leads us to a Monte-Carlo based algorithm. The result of using this approach are presented and discussed.

’Flight’ is a program that uses flight mechanics to estimate the flight range of birds. This program, used by ornithologists, is only available for Windows OS. It requires manual imputation of body measurements and constants (one observation at a time) and this is time-consuming. Therefore, the first task is to implement the methods in R, a programming language that runs on various platforms. The resulting package named flying, has three advantages; first, it can estimate flight range of multiple bird observations, second, it makes it easier to experiment with different settings (e.g. constants) in comparison to Flight and third, it is open-source making contribution relatively easy. Uncertainty and global sen- sitivity analyses are carried out on body measurements separately and with various con- stants. In doing so, the most influential body variables and constants are discovered. This task would have been near impossible to undertake using ’Flight’. A comparison is made amongst the results from a crude partitioning method, generalized additive model, gradi- ent boosting machines and quasi-Monte Carlo method. All of these are based on Sobol’s method for variance decomposition. The results show that fat mass drives the simulations with other inputs playing a secondary role (for example mechanical conversion efficiency and body drag coefficient).

Une caractéristique unique de l'environnement spatial de Mercure est le fort couplage qui existe entre la surface, l'exosphère, la magnétosphère et le vent solaire. Ce système peut être étudié par des méthodes de télédétection embarquées sur les missions spatiales telles que Mariner 10, MESSENGER et bientôt BepiColombo, ainsi que par les observatoires au sol. L'exosphère de Mercure est un milieu complexe avec seulement quelques espèces détectées jusqu'ici, dont l'hydrogène atomique H. H a seulement été détecté une fois par la sonde Mariner 10 en 1974-1975 et représente un traceur de l'interaction entre le vent solaire et la planète Mercure. L'instrument PHEBUS 'a bord de la mission ESA/JAXA BepiColombo vers Mercure est un spectromètre double canal EUV-FUV capable de détecter les émissions les plus faibles, comme H I Lyman-α 'a 121.6 nm. La première partie de cette thèse se concentre sur la modélisation radiométrique et la simulation des performances de PHEBUS. Pour préparer la calibration spectrale en vol et pendant la phase orbitale, un ensemble d'étoiles de référence est déterminé et évalué pour tirer partie au mieux de la résolution et du domaine spectral du détecteur. Des prévisions sur la possibilité de détection des raies d'émission exosphériques sont également données (science performance). Comme PHEBUS est basé sur SPICAV, le spectromètre UV de Venus Express, des techniques semblables de calibration spectrale peuvent être utilisées. Une étude des occultations stellaire de SPICAV est réalisée dans la deuxième partie de cette thèse. Les spectres des étoiles sont extraits, analysés et convolués avec la fonction instrumentale en vue de préparer les futures observations de PHEBUS. Les résultats sont disponibles dans la base de données de calibration du groupe de travail 'a l'ISSI Cross-calibration of past FUV experiments . En parallèle aux nouveaux instruments de grande sensibilité et à haute résolution spectrale, comme PHEBUS, le développement de simulations numériques est nécessaire 'a la compréhension de l'exosphère de Mercure. La troisième partie de cette thèse présente le modèle SPERO, premier modèle auto-cohérent 3D Monte Carlo dédié 'a l'hydrogène exosphérique de Mercure, prenant en compte toutes les sources et les pertes, tels que la désorption thermique, la photoionisation ou la pression de radiation solaire. La désorption thermique est par hypothèse la source dominante d'hydrogène exosphérique. La densité surfacique ainsi que les densités, températures et vitesses exosphériques sont calculées jusqu'à 8 rayons mercuriens. Une étude de sensibilité est effectuée en se basant sur les incertitudes dans les mécanismes de source et de perte, donnant lieu à des asymétries jour/nuit en densité et en température. En utilisant les densités calculées dans un modèle de transfert radiatif, il est possible de comparer les sorties de SPERO avec les données d'émission Lyman-α de Mariner 10, et d'anticiper le retour de données hydrogène grâce 'a l'instrument MASCS embarqué sur la mission MESSENGER de la NASA.

L'exosphère de Mercure est complexe avec juste quelques espèces détectées, dont l'hydrogène atomique. Un partie de la thèse présente la modélisation radiométrique de PHEBUS, un spectromètre EUV-FUV capable de détecter les émissions comme Lyman-alpha, à bord de la mission ESA/JAXA BepiColombo. Des prévisions sur la possibilité de détection des raies d'émission exosphériques sont données, grace a un ensemble d'étoiles de référence, déterminé et évalué. L'autre partie de la thèse présente le modèle SPERO, premier modèle 3D Monte Carlo dédié à H exosphérique, prenant en compte toutes les sources/pertes, comme la désorption thermique-la source dominante H, la photoionisation ou la pression de radiation solaire. Les densités, températures et vitesses exosphériques sont calculées. Une étude de sensibilité est effectuée et en utilisant les densités calculées avec transfert radiatif, il est possible de comparer les sorties de SPERO avec les données d'émission Lyman-alpha de Mariner 10.

The work focuses on Monte Carlo simulations for finding the optimal back scatter time-of-flight spectrometer design for concept testing at the NESSA facility at Uppsala University. The spectrometer consists of two scintillator detectors, D1 (placed in a neutron beam) and D2 (placed in front of D1), at some distance from each other. A fraction of the neutrons that impinge on D1 back scatter into D2 and information on the neutron energy distribution is acquired using the time-of-flight method. For the given constraints on geometry, resolution and efficiency a best resolution was found to be 6.6% with a corresponding efficiency of 1E-4 which gives a sufficient count rate for a neutron generator producing 1E+11 neutrons/s. In order to achieve a minimum of 10 000 counts/h with the same setup a D2 with an area of at least 7 cm^2 is required.

Research suggests what leaders should do or the qualities or characteristics they should have to be ethical leaders (Brown & Treviño, 2006). The ethical decision-making process that leaders should follow to avoid scandals and unethical behavior are overlooked. Few studies focused on ethical decision-making within higher education. Yet, educational leaders have an ethical responsibility that may be even more complex than those of other leaders due in part to increasingly diverse student populations enrolled in higher education that is having an impact on the growth of educational institutions on a global basis (Shapiro & Stekfovich, 2011). Further, ethical scandals are no longer contained by national borders. The rapid growth of technology coupled with changes in political and societal landscapes has advanced ethical scandals to global prominence. A more collective need to understand ethical values and ethical decision-making practices on a global level has emerged. To be globally effective, leaders must be aware of the similarities and differences across and within cultures that could influence business practices (Resick, Hanges, Dickson, & Mitchelson, 2006). However, cross-cultural research has not yet addressed the topic of ethical decision-making. In this study, the ethical decision-making process of higher education was not only examined in the United Stated but also in Poland. This exploratory study used the Delphi research technique to identify an ethical decision-making definition that higher administration leaders in both the United States and Poland use to make ethical decisions and identify the environmental factors that influence their decisions. Findings showed that the United States and Polish expert panels were different and showed very little in common in the identification of a definition and environmental factors. Lastly, both sets of experts identified a new process for ethical decision-making, each constructing a different ethical decision-making process model. This research on ethical decision-making provided evidence that the Polish and United States cultures are not as similar as identified in previous studies in terms of how they identify ethical decision-making and the factors they identify with influencing ethical decision-making. Using this information will create a better understanding of the practices and approaches to ethics that leaders use because of the huge influence they have and exert on people within their own organization and society around them.

A method is introduced to consider flush air data system (FADS) pressures using a technique based on inertial navigation to reconstruct the trajectory of an atmospheric entry vehicle. The approach augments the recently-developed Inertial Navigation Statistical Trajectory and Atmosphere Reconstruction (INSTAR), which is an extension of inertial navigation that provides statistical uncertainties by utilizing Monte Carlo dispersion techniques and is an alternative to traditional statistical approaches to entry, descent, and landing trajectory and atmosphere reconstruction.

The method is demonstrated using flight data from the Mars Science Laboratory (MSL) entry vehicle, which contained an inertial measurement unit and a flush air data system called the Mars Entry Atmospheric Data System (MEADS). An MSL trajectory and atmosphere solution that was updated using landing site location in INSTAR is first presented. This solution and corresponding uncertainties, which were obtained from Monte Carlo dispersions, are then used in a minimum variance algorithm to obtain aerodynamic estimates and uncertainties from the MEADS observations. MEADS-derived axial force coefficient and freestream density estimates and uncertainties are also derived from the minimum variance solutions independent of the axial force coefficients derived from computation fluid dynamics (CFD), which have relatively high a priori uncertainty. Results from probabilistic analyses of the solutions are also presented.

This dissertation also introduces a method to consider correlated CFD uncertainties in INSTAR. From a priori CFD uncertainties, CFD force and pressure coefficients are dispersed in a Monte Carlo sense and carried over into the reconstructions. An analysis of the subsequent effects on the trajectory, atmosphere, and aerodynamic estimates and statistics is presented.

Trajectory, atmospheric, and aerodynamic estimates compare favorably to extended Kalman filter solutions obtained by the MSL reconstruction team at NASA Langley Research Center. The uncertainties obtained through the methods from this work are generally smaller in magnitude because of assumptions made regarding sources of error in the MEADS pressure transducer uncertainties. Using data-derived uncertainties in the pressure measurement noise covariance results in aerodynamic parameter estimate uncertainties that are in better agreement with the uncertainties derived from the Monte Carlo dispersions. CFD database errors dominate the uncertainties of parameters derived from aerodatabase axial force coefficients.

Helicopters are often used to transport supplies and equipment. When a heavy load is carried via suspension cables below a helicopter, the load oscillates in response to helicopter motion and disturbance forces, such as wind. This oscillation is dangerous and adversely affects control of the helicopter, especially when carrying large or heavy loads. By adding input shaping to the helicopter's flight controller, the suspended load oscillation caused by helicopter motion is greatly reduced. A significant benefit of this approach is that it does not require measurement of the load position. This thesis contains derivations and analysis of simple planar helicopter-load dynamic models, and these models are verified using experimental data from model-scale, radio-controlled helicopters. The effectiveness of input shaping at eliminating suspended load oscillation is then demonstrated on this experimental hardware. In addition, the design of an attitude command, near-hover flight controller that combines input shaping and a common flight control architecture is illustrated using dynamic models of a Sikorsky S-61 helicopter, and simulation results are shown for example lateral and longitudinal repositioning movements. Results show that applying input shaping to simulated pilot commands greatly improves performance when carrying a suspended load.

A back scatter time of flight neutron spectrometer consisting of two scintillation detectors is simulated in Geant4 to examine whether it is possible to perform a proof of concept test at the NESSA facility at Uppsala University. An efficiency of ε = 2.45 · 10^-6 is shown to be large enough for a neutron generator intensity of 1.9 · 10^10 neutrons per second to achieve a minimal required signal count rate of 10000 counts per hour. A corresponding full width at half maximum energy resolution of 8.3% is found. The background in one of the detectors is simulated in MCNP and found to be a factor 62 larger than the signal for a given set of pulse height thresholds in the detectors. Measures to increase the signal to background ratio are discussed and an outlook for future work concerning testing the spectrometer at NESSA is presented.

Abstract Light scattering diagnostics of turbid media containing both structural and dynamic inhomogeneities is currently of significant importance. One of the important directions in modern light scattering diagnostics is the development of methods for probing biological media with visible- and near-infrared radiation allowing for visualization of the biotissue structure. Optical methods for studying the biotissue structure and characterization of its optical properties are very promising and have been rapidly developing during the past decade. The present work is aimed at improving and discovering new potentials of currently existing methods of laser diagnostics of biological tissues containing both structural and dynamic inhomogeneities. In particular, the feasibilities of spatially resolved reflectometry and time-of-flight techniques for the problem of noninvasive determination of glucose level in human blood and tissues were examined both numerically and experimentally. The relative sensitivities of these methods to changes in glucose level were estimated. Time-of-flight technique was found to be more sensitive. The possibilities of Doppler optical coherence tomography for imaging of dynamic inhomogeneities with high resolution were considered. This technique was applied for the first time for the imaging of complex autowave cellular motility and cytoplasm shuttle flow in the slime mold Physarum polycephalum. The effect of multiple scattering on the accuracy of the measured flow velocity profiles for the case of single flow and for the case of the flow embedded into the static medium with strong scattering was studied. It was shown that this effect causes significant distortion to the measured flow velocity profiles and it is necessary to take this into account while making quantitative measurements of flow velocities.

Cette thèse a pour but d'étudier le transport de charges pho- togénérées dans des matériaux hybrides composés de polymères π-conjugués et de nanocristaux de semi- conducteurs, conçus pour des applications en opto-électronique. La synthèse chimique permet d'obtenir des nanocristaux de CdSe à l'échelle du gramme ayant une faible polydispersité et des formes contrôlées (sphériques, branchées). Les ligands de surface des nanocristaux de CdSe sont échangés par de petites molécules (pyridine, éthanedithiol, phénylènediamine, butylamine, benzènedithiol) afin d'augmenter leur conductivité. L'échange de ligands modifie les niveaux énergétiques des nanocristaux, comme le montrent des études optiques et électrochimiques. Le poly(3-hexylthiophène) déposé sous forme de couches minces présente différents degrés de couplage intermoléculaire et de désordre énergétique selon la méthode de dépôt et le solvant utilisé. Dans les films hybrides, des mesures de diffraction de rayons X en incidence rasante montrent que la structuration cristalline de la matrice organique est modifiée par la présence des nanocristaux. Les mesures de Temps-de-Vol dans les couches hybrides montrent que les mobilités des trous et des électrons varient avec le contenu en nanocristaux, ainsi qu'avec leur forme et leurs ligands. De faibles fractions de nanocristaux provoquent une amélioration de la mobilité des trous, tandis que de plus grandes fractions la détériorent. Les mobilités électroniques sont soumises à une fraction-seuil, as- similable à un seuil de percolation. La fraction optimale de nanocristaux, du point de vue des mobilités des trous et des électrons, est de 36% en volume pour les nanocristaux sphériques avec les ligands de synthèse. Enfin, les simulations Monte-Carlo des courants transitoires photo-générés, dans un échantillon de poly(3-hexylthiophène) et dans un hybride, montrent d'une part que la distribution énergétique du poly(3-hexylthiophène) domine l'allure des courants simulés et d'autre part que les nanocristaux peuvent être assimilés à des sites difficilement accessibles du réseau cubique
The aim of this work is the study of photogenerated charge transport in hybrid films composed of π-conjugated polymers and of semiconductor nanocrystals, designed for applications in optoelectronics. Chemical synthesis provides gram-scale samples of CdSe nanocrystals, of low polydispersity and con- trolled shapes (spherical, branched). In order to enhance their conductivity, the surface ligands of CdSe nanocrystals (stearic acid, oleylamine) are exchanged by smaller molecules, namely pyridine, ethanedithiol, phenylenediamine, butylamine and benzenedithiol. Optical and electrochemical studies show that the lig- and exchange modifies the nanocrystals' energy levels. Poly(3-hexylthiophene) thin films exhibit varying degrees of energetical disorder and of intermolecular coupling, depending on the processing method and on the solvent used. In hybrid films, the crystallinity of P3HT, probed by grazing incidence X-ray diffraction, is modified by the presence of nanocrystals. Time-of-Flight measurements of hybrid films show that elec- tron and hole mobilities vary with the content of nanocrystals, with their shape, and with their ligands. Small volume fractions of nanocrystals enhance the hole mobility, and large fractions degrade it. Electron mobilities are percolation-limited: they reach a stable value for a threshold fraction of nanocrystals. The optimal fraction of nanocrystals for electron and hole mobilities is 36 vol% in hybrids made of spherical nanocrystals with their synthesis synthesis ligands. Finally, Monte Carlo simulations of photogenerated current transients in pristine poly(3-hexylthiophene) and in a hybrid sample show on one hand that the energy distribution of poly(3-hexylthiophene) rules the shape of the simulated transients, and on the other hand that nanocrystals can be described as little accessible sites of the hopping lattice

Esta dissertação apresenta uma avaliação do comportamento de estacas hélice contínua quanto à capacidade de carga, ao recalque e à segurança e confiabilidade, a partir de um cenário de análise em que foi considerado um banco de dados de 58 provas de carga estáticas, realizadas em estacas hélice contínua de 13 obras distintas. Esta pesquisa está focada principalmente no comportamento carga-recalque e confiabilidade de fundações em estacas hélice contínua. Nesta análise foi também verificada a aplicabilidade do método proposto por Aoki (1989) para determinação da curva carga-recalque destas provas de carga. Os valores de capacidade de carga medidos foram comparados com os previstos pelos método Aoki & Velloso (1975), o método Decourt & Quaresma (1978), o método de Cabral (1996), e o método Alonso (1996). Estes métodos também foram utilizados para previsão de transferência de carga nas estacas, necessária para a previsão da curva carga-recalque pelos método de Aoki (1989). Adicionalmente, com os resultados das provas de carga foram estimadas para cada obra a probabilidade de ruína da fundação, e de ocorrência de recalques superiores a um valor limite.
This dissertation presents an evaluation of the behavior of continuous flight auger piles on ultimate capacity, settlments, safety and reliability, from a scenario analysis in which we considered a database of 58 static load tests, performed on piles of 13 distinct sites. However, this research is focused on the loaddisplacement behavior and reliability of this type of foundation. This analysis also verified the applicability of the method proposed by Aoki (1989) to determine the load-displacement curve of these pile load tests. The values of measured pile capacity were compared with those provided by the method Aoki & Velloso (1975), the method Decourt & Quaresma (1978), the method Cabral (1996), and the method Alonso (1996). These methods were also used to predict the load transfer along the piles, necessary to predict the load-displacement curve by the method of Aoki (1989). Additionally, the results of these load tests were used to estimate the probability of failure of the foundations tested, and the occurrence of settlements exceeding a threshold value.

The electrical properties, in particular the U–I characteristics, current and voltage signal shapes within the pulse, are important parameters for the understanding of the processes taking place in the pulsed glow discharge (PGD). The electrical properties are also closely related to the analytical performance of the PGD such as sputtering rates, crater shapes and emission yields. Moreover, the dependence of the U–I plots on the density of the discharge gas can be used to estimate the gas temperature. This result is relevant for the analysis of thermally fragile samples. Nevertheless, there is a lack of PGD studies where the current and voltage signals are considered in detail. Therefore, this article is dedicated to the electrical properties of PGD. The influence of the PGD parameters (duty cycle and pulse duration) on the electrical properties is examined. The results highlight the optimum parameters for particular analytical applications. The question, whether direct current (dc) and radio frequency (rf) discharges behave similarly is also discussed and all experiments are performed for both modes. The comparative studies reveal strong similarities between dc and rf pulsed discharges
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

The electrical properties, in particular the U–I characteristics, current and voltage signal shapes within the pulse, are important parameters for the understanding of the processes taking place in the pulsed glow discharge (PGD). The electrical properties are also closely related to the analytical performance of the PGD such as sputtering rates, crater shapes and emission yields. Moreover, the dependence of the U–I plots on the density of the discharge gas can be used to estimate the gas temperature. This result is relevant for the analysis of thermally fragile samples. Nevertheless, there is a lack of PGD studies where the current and voltage signals are considered in detail. Therefore, this article is dedicated to the electrical properties of PGD. The influence of the PGD parameters (duty cycle and pulse duration) on the electrical properties is examined. The results highlight the optimum parameters for particular analytical applications. The question, whether direct current (dc) and radio frequency (rf) discharges behave similarly is also discussed and all experiments are performed for both modes. The comparative studies reveal strong similarities between dc and rf pulsed discharges.
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

A Monte Carlo simulation of the Neutron Wall detector system has been performed using Geant4, in order to define optimum conditions for the detection and identification of multiple neutrons. Emphasis was put on studying the scattering of neutrons between different detectors, which is the main source of the apparent increase of the number of detected neutrons. The simulation has been compared with experimental data. The quality of neutron gated γ-ray spectra was improved for both two- and three-neutron evaporation channels. The influence of small amounts of γ rays mis-interpreted as neutrons was investigated. It was found that such γ rays dramatically reduce the quality of neutron gated γ-ray spectra.

The interaction properties of fast neutrons in a closed-end coaxial and a planar high-purity germanium detector (HPGe) were studied. Digitised waveforms of HPGe preamplifier signals were recorded for time-of-flight separated neutrons and γ rays, emitted by a ²⁵²Cf source. The experimental waveforms from the detectors were compared to simulated pulse shapes. In the analysis, special emphasis was given to the detection of elastically scattered neutrons, which may be an important effect to take into account in future spectrometers based on γ-ray tracking. No differences between neutron and γ-ray induced pulse shapes were found in this work.

A Monte Carlo simulation of the interactions of fast neutrons in the future 4π γ-ray spectrometer AGATA was also performed, in order to study the influence of neutrons on γ-ray tracking. It was shown that although there is a large probability of detecting neutrons in AGATA, the neutrons decrease the photo-peak efficiency of AGATA by only about 1% for each neutron emitted in coincidence with γ rays. The peak-to-background ratios in γ-ray spectra are, however, reduced to a much larger extent. The possibility of using AGATA as a neutron detector system was also investigated.

Este trabalho discutiu o estudo da inferência de carregamento e a reconstrução fratográfica da taxa de propagação da trinca por fadiga em histórias de vôos simulados do tipo Twist, mini-Twist, Falstaff e mini-Falstaff. O material estudado foi uma liga de alumínio de grau aeronáutico SAE-AMS 7475 T7351 na qual foram obtidas as propriedades mecânicas a partir dos ensaios de tração e dureza, análise química, metalográfica. Foram realizados ensaios de amplitude constante de carregamento em corpos de prova com geometria tipo C(T) extraídos de um bloco e ensaios de amplitude variável em corpos de prova com geometria tipo M(T) extraídos de uma placa. Corpos de prova do tipo C(T) foram extraídos da orientação L-T e T-L, à temperatura ambiente com diferentes espessuras para a realização de ensaios de propagação de trinca por fadiga (da/dN vs. ΔK) com distintos valores de razão de carregamento,R (0,1;0,3; 0,5; 0,7 e 0,8) de acordo com a norma ASTM-E647 (1993). Foram realizados dois tipos de ensaios de fadiga com amplitude constante de carregamento. Primeiro, o ensaio com ΔP constante para obtenção dos dados dos estágios II e III das curvas da/dN vs. ΔK para distintos valores de R e, posteriormente, o ensaio com ΔK constante e R crescente para ser utilizado no estudo da inferência de carregamento de amplitude constante a partir da relação entre a morfologia da estria, H/s e a razão de carregamento R. Adicionalmente foram realizados ensaios de tenacidade à fratura, nas direções L-T e T-L, conforme a norma ASTME1820 (1999). As taxas de propagação macroscópica e microscópica foram comparadas e boas correlações foram obtidas para um intervalo entre 0,1 a 1,0 μm/ciclo, mesmo com distintos R. Através da técnica proposta por Berkovitz (1995), o espectro de carregamento foi estimado para distintos valores de R, através da técnica de parametrização do fator K e os resultados foram comparados ao espectro de carregamento real imposto pela máquina de ensaio. Após os ensaios de amplitude constante de carregamento foram realizados ensaios de amplitude variável com a aplicação em corpos de prova M(T) de espectros de vôos simulados padronizados pela NLR do tipo Twist e Falstaff e seus vôos reduzidos, mini-Twist e mini- Falstaff, em uma máquina servohidráulica de ensaios dinâmicos. A partir destes ensaios notou-se que suprimir os vôos com os carregamentos menos severos influencia muito a vida da propagação da trinca de fadiga, quando vôos simulados do tipo Twist e mini-Twist, fato este não observado para o Falstaff e mini-Falstaff. Foi possível observar também o efeito da aceleração e desaceleração da trinca por fadiga observando os gráficos de d2a/dvôo vs. a obtidos dos ensaios de amplitude variável. Foi realizado um estudo da superfície de fratura do CP05 por meio da técnica fractográfica do reconhecimento de blocos marcadores sendo possível mostrar uma satisfatória reconstituição da taxa de propagação da trinca por fadiga de vôo simulado do tipo Falstaff por meio de medidas das marcações na superfície de fratura dos vôos mais severos, realizadas em imagens obtidas por MEV.
The loading inference and the fractographic reconstruction of fatigue crack propagation rate in simulated flight stories, as Twist, mini-Twist, Falstaff and mini-Falstaff were investigated in this work. The studied material was an aluminum alloy SAE-AMS 7475 T7351. Tensile and hardness tests were carried out in order to determine mechanical properties, as well as chemical and microstructure analysis of the material. C(T) specimens were extracted from a block of material for constant amplitude load testing and M(T) specimens were extracted from a plate and were tested in variable amplitude loading. The curves (da/dN vs. ΔK) for constant-amplitude loading were obtained from fatigue crack propagation tests performed in L-T and T-L directions in C(T) specimens for R (0.1; 0.3; 0.5; 0.7 and 0.8), at room temperature, according to ASTM-E647 (1993). Two different constant loading fatigue tests were performed. At constant ΔP and distinct values of R for obtaining data of stages II and III of da/dN - ΔK curves; and at constant ΔK and increasing the R ratio to be used in the inference of constant amplitude loading in the relation of H/s striation morphology (obtained from fractographic images) and the loading ratio, R. Additionally, fracture toughness tests were executed in T-L and L-T directions, according to ASTM-E1820 (1999). The macroscopic and microscopic fatigue crack propagations were compared and good correlation was obtained for the range 0.1-1.0 μm/cycle, for all R values. By using the K factor parametrization method, Berkovitz (1995), the loading spectrum was estimated for the distinct R-values and the results were compared to the actual spectrum imposed by the test machine. Variable amplitude tests were performed in M(T) specimens by applying simulating flight spectra normalized by NLR, as Twist, mini-Twist, Falstaff and mini-Falstaff, in a servohydraulic test machine MTS, in which a Flextest GT controller was coupled. The suppression of less severe loading flights showed a great influence in fatigue crack propagation life, in simulated flight tests Twist and mini-Twist, but not in Falstaff and mini-Falstaff. The acceleration and slowing down of fatigue crack were observed in the d2a/dflight - a curve obtained from variable loading tests. The fractured surfaces of some samples were examined by the fractographic technique of blocking marks recognition. A good reconstitution of fatigue crack propagation rate of a simulated flight like Falstaff was obtained by the measurements of marks in the fracture surfaces of the more severe flights, in MEV images.

碩士
國立交通大學
運輸科技與管理學系
92
Abstract The global economics affects airline market deeply. Especially when economics comes to a slump situation, airlines may encounter losses of both passengers and cargo if they just considered reducing flight frequency. Teodorovic (1988) pointed out that “proper insight passengers’ transportation demand and the distribution of this demand over time can increase the number of air transportation passengers by offering an adequate number of flights at suitable times.” Hence, it is important for airlines to plan the optimal flight arrival and departure time and flight frequency to maintain business profit under changing economic situation. This study analyzes decisions on flight departure time zones under different economic situations for airlines which operate air services for both passengers and cargos. Factors considered in the study include time lag, flight flying time, flight delay, preferred arrival and departure time of passengers and cargos, the beginning time and the ending time in destination and origination, etc. Since airlines couldn’t make all flights departure time meet the demand of passengers and cargo owners. The study introduces discount functions for tickets and freight charges for flights with various schedule delay. The more the flight departure time satisfies the schedules of passengers and cargo owners, the higher the load factor of the flight. The study further formulates a model using mathematical programming method by maximizing airlines’ profits to find out the optimal departure time zone and frequency for all flights. Furthermore, the study proposes partial-market time-slot allocation scheme using Weighted approach and Analytical approach and estimate their difference in airlines’ profits. The Weighted approach uses the ratio of the profit of individual time zone divided by total profit of airlines as weights to determine the auction price of different time zones. The Analytical approach deduced the range and the maximum value of individual time zone through analyzing profit and cost of the time zone. The study further estimates and compares the total profits of two methods. Finally, the study demonstrates a case study and collects necessary data to show the feasibility of the model. The results of the study show that the model can determine the optimal departure time-zone and flight frequency which maximizies airlines’ profit. Time-slot allocation scheme is better than non time-slot allocation scheme under different economic situations. Furthermore, although the amount of total profits for all airlines is smaller if airport authority adopts partial-market time-slot allocation scheme rather than historic precedence allocation scheme. Nevertheless, it can enable airlines to use time-slot more efficiently through auction scheme. For partial-market time-slot allocation scheme, airlines earn more profits using Weighted approach than analytical approach.

碩士
國立臺灣海洋大學
航運管理學系
92
Abstract Air cargo industry has been booming for the past several decades, and it is considered a very promising growth in the future. Taiwan is situated at Asia’s important transportation center, and air cargo service plays an important role in Taiwan’s economics developing. Take Taiwan airlines for example; air cargo business has a growing up ratio of revenue. It is very important to airlines to design an efficient flying network for their customers. In this research, given some necessary operating data, we develop an integrated model by combining airport selecting and fleet routing, with the objective of maximizing the operating profit, subject to the related operating constraints. Using mathematical programming software, CPLEX 7.1, in conjunction with C programs developed by this study is used to solve the problem. Finally, to evaluate the model and the solution algorithm, we perform a case to study using real cargo operating data from a major Taiwan airline. Keywords: air cargo, network flow problem, fleet routing, airport selecting, mathematical programming

碩士
國立交通大學
運輸工程與管理系
88
The interactions among airline cargo demand, route flight frequency, and aircraft type are of such significance to necessitate using system analysis approach on airline cargo network problems. Past studies concerning airline network design, and flight frequency determination were mostly focused on developing mathematical programming models, or aimed at designing solution algorithms for above models. Few studies integrated changes in cargo demand resulted from the competition between airlines into route flight frequency and aircraft type determination problems for airline cargo network. On the other hand, most of studies concerning airline competition merely apply economic theory or statistical method to deal with air passenger markets; while few of them combine economic theory and network model to deal with air cargo markets and network design. In response to these, this study will explore airline cargo demand and network design problem via constructing models based on the combination of network model and economic theory to reflect the close demand-supply interaction in a competitive air cargo market. This study develops a model for determining the optimum flight frequency and aircraft type on each of all routes operated by an air cargo carrier in a competitive environment. The model is composed of two submodels which include a shipping alternative choice model for shippers and a route aircraft type and flight frequency planning model for airlines. The shipping alternative choice model assumes shippers with different demand characteristics choose the alternative with the least transportation and inventory costs among a choice set which comprises a variety of alternatives represented by competitive airline route service. The route aircraft type and flight frequency planning model is formulated using mathematical programming model by maximizing airlines’ profits to determine the optimum aircraft type and flight frequency on each routes under many-to-many demand pattern. The demand-supply interactions between air carriers and shippers are analyzed by integrating two submodels. The study also designs the solution algorithm to determine the optimal air cargo flight frequency and aircraft type on each of all routes. Finally, we illustrate a real airline cargo network and collecting necessary data to prove the feasibility of the model and to show the significance of results. The results of the study not only can be a building block for future studies in the area of air cargo market and network design problems, but can shed light on marketing, route flight frequency and aircraft type planning related issues for air cargo carriers to be competitive in response to changes in demand.

Spacecraft design is inherently difficult due to the nonlinearity of the systems involved as well as the expense of testing hardware in a realistic environment. The number and cost of flight tests can be reduced by performing extensive simulation and analysis work to understand vehicle operating limits and identify circumstances that lead to mission failure. A Monte Carlo simulation approach that varies a wide range of physical parameters is typically used to generate thousands of test cases. Currently, the data analysis process for a fully integrated spacecraft is mostly performed manually on a case-by-case basis, often requiring several analysts to write additional scripts in order to sort through the large data sets. There is no single method that can be used to identify these complex variable interactions in a reliable and timely manner as well as be applied to a wide range of flight dynamics problems. This dissertation investigates the feasibility of a unified, general approach to the process of analyzing flight dynamics Monte Carlo data. The main contribution of this work is the development of a systematic approach to finding and ranking the most influential variables and combinations of variables for a given system failure. Specifically, a practical and interactive analysis tool that uses tractable pattern recognition methods to automate the analysis process has been developed. The analysis tool has two main parts: the analysis of individual influential variables and the analysis of influential combinations of variables. This dissertation describes in detail the two main algorithms used: kernel density estimation and nearest neighbors. Both are non-parametric density estimation methods that are used to analyze hundreds of variables and combinations thereof to provide an analyst with insightful information about the potential cause for a specific system failure. Examples of dynamical systems analysis tasks using the tool are provided.

碩士
國立交通大學
運輸科技與管理學系
94
With the trend of world trade and free competition, many international industries deliver their goods by air transportation so as to improve their competition after considering shipping distance, time and quality. Taiwan took part in the World Trade Organization in 2001 to increase its competition in the world. Moreover, the structure of industries in Taiwan has been changing from labor intensive to technical intensive while many firms have moved their plants to Mainland China recently. World Air Cargo Forecast 2004/2005 by Boeing shows that the demand of air cargo will be increased up to three times in the future 20 years with an average annual growth rate of 6.2%. Many evidences indicate the importance of air freight. Past studies merely applied the discrete choice model on air carrier choice or directly analyzed the aggregate demand. Little research incorporated the demand-supply interaction into air routes and frequencies programming. This study assumes shippers in specific industry choose air cargo carrier by minimizing the total logistics cost. This study then constructs a demand model to examine how the characters of products, the urgency, shipping fare, inventory cost, shipping time and distance affect international firms’ choices on air carriers. Grey model is used to estimate the air freight demand of each industry. Considering the changes in industrial structure, this study forecasts the air cargo demands on different routes for various firms in different industries. In addition, a supply model is constructed to determinate route frequencies and the unit basic shipping charge for air carriers with demand-supply interaction. A case study is presented to illustrate the application of the proposed model using data available from C.K.S international airport and industrial economics data base in Taiwan. The results show that shippers with the shorter delivery distance put more emphasis on shipping charge. However, they will prefer choosing the air cargo carrier which offers more frequencies when their product value is high. Since the product value of goods transported from Taipei to Anchorage in US is high, therefore, shippers on this route usually emphasize on the inventory cost and choose high-frequency air cargo firms. The predicted demand using the proposed model is shown to be more accurate than those without considering the changes in industrial structure. Moreover, the proposed model is demonstrated to yield more profit than the model that does not consider demand-supply interactions. Consequently, the results of this study not only indicate that the route frequency programming model for air cargo carriers with demand-supply interaction is practicable, but also provide decision-support tools that forecast the air freight demand and profit as well as determine route frequencies and unit basic shipping charge for air cargo carriers.

Measured powder diffraction patterns contain contributions from the sample and the instrument. Most available data analysis software operates on the measured data to extract sample parameters, however, few programs can take sample parameters and rigorously simulate the expected diffraction profile for a given instrument. In this work Monte Carlo methods, within the framework of McStas software, are used for the simulation of neutron diffraction at the SMARTS (Spectrometer for Materials Research at Temperature and Stress) diffractometer in the Los Alamos Neutron Science Center. The simulations include all the instrumental components, such as the moderator, guide system, collimator, detector banks and sample. The results of the simulations are in excellent agreement with the experimental data for different ideal powder samples. The simulations also yield information on the line broadening introduced into the diffraction profile as a function of energy and are used to predict the size and strain limit above which line broadening studies cannot be performed on this instrument. Theoretical derivations of line profile analysis are presented to provide an accurate explanation of the formation of diffraction peaks from the powder sample. This thesis demonstrates how rigorous scattering theory can be used to design optimal diffraction instruments.

碩士
國立嘉義大學
運輸與物流工程研究所
91
Hub-and-Spoke network has been wildly used in the airline operations. In the design of a hub-and-spoke network, it is usually to determine the number of hubs and their locations first, and then the airline service network is established based on the given hubs. However, the efficiency of a service network highly depends on hub locations. Therefore, the above two-steps procedure cannot reach the overall system optimal operation. Practically, for a airline carrier, there are three possible service policies in a hub-and-spoke system, direct flight, hub connected flight, and coexistence of both flights. However, the past studies only addressed the problems with direct and hub connected services. This study developed a unified model to determine hub number, hub location, and flight service network simultaneously. The model is also able to consider three possible service policies. The model is formulated as a mix-integer program. A mathematical programming software, CPLEX 7.1, in conjunction with C programs developed by this study is used to solve the problem. Finally, the air freight data between Taiwan and Mainland China is used as a case study to illustrate the model performance.

The present work focused on the implementation and validation of an in-flight thrust measuring system using onboard instrumentation. This system was integrated and tested onboard the 01¬harapo UAV, from the Aerospace Sciences Department of University of Beira Interior, resulting from the need to have a fully equipped and instrumented flying test bed to assess and validate variable span wings prototypes using morphing technologies. This system comprises a force transducer (load cell) and a compatible signal conditioner which filters and amplifies the load cell signal. An infra-red temperature sensor was also added to the system in order to correct the thrust readings for temperature effects. The load cell signal conditioner and temperature sen¬sor communicate with the UAV flight management unit which works as data acquisition system. The in-flight parameters regarding propeller thrust and load cell temperature can be real-time monitored. The load cell was completely characterised in terms of its calibration curves both within and without the compensated range. Then, an assessment was conducted to quantify the UAV transmission shaft friction magnitude. Thereafter, with both the load cell calibration curves and with the friction compensation equation, the final in-flight thrust equations were found and implemented into the UAV flight management unit. At this stage, the entire in-flight thrust measuring system was characterized in terms of its performance, that is, in terms of its non-repeatability, non-linearity, hysteresis and creep. Regarding the system validation process, in-flight and wind tunnel tests were performed. These tests were conducted for different air¬speeds and different throttle settings in order to obtain thrust values for different propeller advance ratios. An uncertainty analysis was also carried out with the aim of attaining the accu¬racy and precision level of the various results obtained. ln general, for lower throttle settings (below 35% of the full throttle), the system seems to have low sensitive to measure low thrust magnitudes. Nevertheless, and despite all the factors that had a negative effect on the mea¬suring system accuracy, for throttle settings above 35% the in-flight thrust values showed a satisfactory agreement with the corresponding wind tunnel ones. For future system iterations, a few enhancements were proposed as well.
O presente trabalho focou-se na implementação e validação de um sistema de medição de tração em voo usando instrumentação a bordo. O sistema foi integrado e testado a bordo da aeronave não tripulada "Olharapo", pertencente ao Departamento de Ciências Aeroespaciais da Universidade da Beira Interior, como necessidade de se ter uma plataforma aérea totalmente equipada e instrumentada a fim de se avaliarem e validarem protótipos de asas de envergadura variável recorrendo a tecnologias morphing. Este sistema é composto por um transdutor de força (célula de carga) e por um condicionador de sinal compatível, o qual filtra e amplifica o sinal da célula de carga. Um sensor de temperatura de infravermelhos foi também adicionado ao sistema com o intuito de corrigir as leituras de tração para efeitos de temperatura. O condicionador da célula de carga bem como o sensor de temperatura comunicam com a unidade de gestão de voo da aeronave não-tripulada, a qual funciona como sistema de aquisição de dados. Os parâmetros de voo relativos à tração da hélice e à temperatura da célula de carga são monitorizados em tempo real. A célula de carga foi completamente caracterizada em termos das suas curvas de calibração, tanto dentro como fora do seu compensated range. De seguida, foi conduzida uma avaliação para quantificar a magnitude do atrito do veio de transmissão da aeronave. Após, com ambas as curvas de calibração da célula de carga bem como com a equação de compensação do atrito, as equações finais para a tração foram encontradas e implementadas na unidade de gestão de voo da aeronave. Nesta fase, todo o sistema de medição de tração em voo foi caracterizado em termos do seu desempenho, isto é, em termos da sua não-repetibilidade, não linearidade, histerese e fluência. No que respeita ao processo de validação do sistema, foram conduzidos testes em voo e em túnel de vento. Estes testes foram realizados para diferentes velocidades de escoamento e para diferentes frações de acelerador de forma a obter valores de tração para diferentes razões de avanço da hélice. Um estudo de análise de incertezas foi também realizado a fim de se perceberem quais os níveis de precisão e exatidão dos diferentes resultados obtidos. No geral, para frações de acelerador reduzidas (abaixo dos 35%), o sistema parece ter pouca sensibilidade para medir baixas magnitudes de tração. No entanto, e apesar de todos os fatores que exerceram um efeito negativo na precisão do sistema, para frações de acelerador acima dos 35%, os resultados de voo exibem uma concordância satisfatória com os seus correspondentes obtidos em túnel de vento. Para futuras iterações do sistema, alguns melhoramentos são também propostos.