Aeronautical Engineering: A continuing bibliography with indexes, supplement 99

This bibliography lists 292 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1978

Thinking through making : the rural building workshop

This thesis is about the link between thinking and making, and how designing and physically building or prototyping what is designed (or parts there of) aids in the generation of ideas, and has a potential for architectural education. The ideas that have transpired through the course of the year from building models and doing research for my theory and technology papers has led me in the direction of developing components and techniques for construction made from easily sourced tools and materials - ones from local industry and the landscape - that give rise to a tectonic expression as well as allows for an adaptable type of architecture. The methodology informing the design has therefore developed from the bottom up through the use of these components, as well as from the top down by means of a structural concept. The first part of the paper looks at the theory of making which deals with aspects of making in current society that I find relevant to this thesis. Part two and three of this paper is comprised of reciprocal components. Part two deals with the theory of structure and how my findings have helped guide the process of making, and have led to an appropriate structural system for my concept of a 'growing' or adaptable building. The third part of this paper describes the models I have built this year to illustrate the concept of 'techne', or the process of creation that is guided by the thing made, in order to demonstrate the qualities that materials possess, as well as how the act of making can be a design generator. It also describes how the initial stage of building models has led to the exploration of structural systems and components, and how models relating to the programme and site have been able to start informing the form of a building. The fourth and final part of this paper looks at the programme, site, and materiality of the 'Rural Building Workshop'

Social work with airports passengers

Social work at the airport is in to offer to passengers social services. The main methodological position is that people are under stress, which characterized by a particular set of characteristics in appearance and behavior. In such circumstances passenger attracts in his actions some attention. Only person whom he trusts can help him with the documents or psychologically

Impacts of Western lifestyles in a telecoupled world:Mapping and specifying current and future demand for ecosystem services

Human use of natural resources is exceeding the planet's ecological ceilings. To reverse this trend, sustainable production and consumption was placed on the global governance agenda at the 1992 Earth Summit in Rio de Janeiro. Since then, a large number of empirical studies have been carried out to characterise the environmental impact of consumption. It has become clear that humanity's pressure on ecosystems is mainly related to the use of natural resources for food, shelter and mobility, and that the wealthiest people contribute disproportionately to the overall pressure because of the consumption culture associated with affluence. It has also been shown that most environmental impacts are not visible to final consumers because the goods and services they use are often produced miles away. This understanding has largely been supported by conceptual and methodological developments around the concepts of lifestyle, ecosystem services and telecoupling. However, these concepts have only been marginally combined so far, leaving open questions about the role of lifestyle in explaining the use of ecosystem services and ecological impacts. This dissertation brings together ideas and methods from research around these concepts to propose indicators and tools to characterise the role of lifestyle as a determinant of the extent and geography of ecosystem services demand and impacts. Different aspects of lifestyle - diet, holiday, mobility - are empirically addressed, with a focus on Western countries where living standards are relatively high and affluent consumption is the norm. Chapter 2 questions the potential ecological outcomes of a large-scale shift from the current standard diet in the United States of America (USA) to more plant-based alternatives. Chapter 3 examines tourist preferences for different holiday styles as a determinant of carbon emissions from leisure travel within the European Union (EU). Chapter 4 draws a quantitative link between current mobility patterns in the European Union and the expansion of rubber plantations in the tropics, which is leading to deforestation. In addition, Chapter 5 critically looks at the trade model used in chapters 2 and 4 to trace the origin of commodities available for use in the USA and the EU and proposes a way forward. Finally, Chapter 6 synthesises the methodological and empirical findings of Chapters 2 to 5 and operationalises these findings into recommendations for businesses and governments on how to support the transition to sustainable consumption in Western societies. Overall, this thesis shows that our understanding of lifestyle as a determinant of ecological impacts can be improved by reusing available large-scale survey results, contextualising individual agency and substantiating indicators of demand for ecosystem services with qualitative information. Taken together, the chapters demonstrate that prevailing preferences in Western societies explain the extent and spatial patterns of demand for ecosystem services and associated impacts. They also highlight the dependence of Western lifestyles on far-flung ecosystems and globalisation processes such as international trade and leisure travel. This body of research therefore re-emphasises the role of demand-side measures in reducing the overall impact of Western societies and the importance of addressing potential impacts beyond borders. Ultimately, this perspective on the role of lifestyle as a driver of sustainability issues in a telecoupled world argues for cooperation between different actors - individual consumers, businesses and governments - to carry out the transition to sustainable consumption patterns

Aeronautical engineering: A continuing bibliography with indexes (supplement 237)

This bibliography lists 572 reports, articles, and other documents introduced into the NASA scientific and technical information system in February, 1989. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Crashworthiness analysis and design optimization of hybrid energy absorption devices: application to aircraft structures

Programa Oficial de Doutoramento en Enxeñaría Civil . 5011V01[Abstract]Amid the main research lines for the enhancement of aircraft and automotive designs, structural optimization and crashworthiness studies are at their pinnacle. Means of transport need to be robust and safe, albeit efficiency and lightness cannot be neglected. While active safety systems have avoided innumerable accidents, passive crashworthiness systems need to protect passengers when they do occur. In the event of a crash, modern structures are designed to collapse progressively, dissipating high amounts of kinetic energy and protecting the passengers against abrupt decelerations. Within this broad field of study, the aim of this thesis is that of bettering traditional crash structures by designing and optimizing thin-walled hybrid energy absorbers, and ultimately proving reduced occupant injury levels during representative impact scenarios. The collapsible energy absorbers studied throughout this research originated by combining square metallic tubes with inner cores made from glass-fiber reinforced polymer (GFRP) and foam structures. Honeycombs are studied in depth, showing their outstanding behavior as load bearing structures and identifying the effects of modifying their cell’s shape. Another composite structure investigated was that of an intertwined four-plate star core, slightly less stiff than honeycombs but promising crushing behavior. Foam extrusions are also used as standalone reinforcements and as filling of the inner core’s voids, always enhancing the energy absorption capabilities of specimens. Specimens are characterized according to different crashworthiness metrics, including their energy absorption value, peak force undergone during its collapse and the mass of the components. Moreover, each initial design is subjected to optimization techniques to achieve the utmost from the aforementioned metrics. For that, finite element simulations of axial dynamic loading are parametrized as to obtain variable core heights, material thicknesses and modifiable honeycomb’s cell size and shape. These are later coupled with sampling and metamodeling algorithms, constructing a surrogate model which performs accordingly with the simulation during any fluctuation in the design variables. Later on, the metamodels are single- and multi-objectively optimized with genetic algorithms, yielding various sets of designs that excel in one or more of the selected responses. As a second goals of this work, the previous energy absorber design and the methodology used are to be applied in a significant impact scenario of a passenger vehicle. A drop-test numerical simulation from a Boeing 737-200 fuselage section is developed and correlated with extensive experimental data, later analyzing the crushing behavior of isolated components and their energy absorption trends. The effect of adding hollow thin-walled tubes as vertical struts is studied, expecting a great enhancement of the conventional design response. Surrogate-based optimization methodologies are also applied to this simulation, monitoring various crashworthiness biometrics and the specimen’s mass. Results show that on a coupon basis, the usage of inner reinforcements can modify the tube’s collapse patterns and increase its specific energy absorption values by up to 30 %, mainly caused by the interaction between the core and the confining structure. Moreover, reducing the core’s height has also shown improved responses, offsetting the triggering loads of each component and yielding peak force values 33 % lower. Topographic optimization of honeycomb cells has revealed that the highest specific energy absorption values for dynamic loads are not achieved with a regular cell but with a pseudo-rectangular one. The usage of foam as cell-filling has also proved superb, increasing energy absorption by another 28 % with minor hindering on the specimen’s mass. As for the validation of the full size aircraft drop-test simulation, numerical and graphical results closely match those of the experimental procedure. It was found that removing the auxiliary fuel tank from the original section increased occupant injury levels due to high structural deformation and low energy absorption by the main structures. In a later phase, hybrid energy absorbers are added to the fuselage section with an empty cargo area, and a new surrogate model is built with 600 full-scale drop test simulation. The surrogate is then single- and multi-objectively optimized, reducing acceleration peak values by 50 % and injury levels from severe to moderate at different occupant locations

Aviation Economics: Safety, Monopsony, and Small Sample Inference

This dissertation consists of three essays on aviation. The first chapter investigates the relationship between competition and airline safety. The U.S. airline industry transports almost a billion passengers a year. Accidents still cause much apprehension and angst among the public; the two 737 Max crashes are the latest examples. Despite massive improvements in safety over the last decades which are largely due to technological improvements, there is still a lack of research done on the effect of market conditions. We provide a simple theoretical model to explain the relationship between safety and competition. Using data from 1995 to 2018, we employ a negative binomial regression to evaluate the impact of competition through the Inverse Herfindahl Hirschman Index, Concentration Ratio 4 and 8, on injury outcome of passengers involved in an airline accident. Since accidents are costly both directly and indirectly through brand image deterioration, a competitive market may incentive airlines to reduce risks of accidents. Meanwhile, since safety is unobserved by passengers, under a highly competitive environment where profit margins are thinner, airlines cut costs, some of which are related to safety. Our result suggests that a less competitive industry has a positive impact on safety, suggesting that excess profits are in part reinvested into safety measures. The second chapter tests the hypothesis that monopsony power is an important determinant of wages and employment in the U.S. pilot labor market. We estimate the labor supply curve of the U.S. airline industry using firm-level employment and accident data from 1995 to 2018. Utilizing a labor demand instrument, the prevalence of aircraft accidents, allows us to directly measure monopsony power. We also investigate the effects of competition, as measured by the Inverse Herfindahl-Hirschman Index, on the labor supply elasticity. We estimate a labor supply elasticity of 2.56, indicating that airlines have substantial monopsony power in pilot hiring, resulting in a labor shortage and wages 28.11% below the marginal revenue products. We also find that as market competition rises, airlines slightly lose market power in hiring: wages increase as competition increases. The source of monopsony power lies elsewhere, mostly in the training and career structure, which we address and provide policy recommendations. The third chapter proposes a new method to calculate the p-values of a treatment variable in a cross-sectional small sample. Causal evaluation is becoming increasingly popular in industry and government. In small sample scenarios inference is more difficult. This often occur for several reasons such as budget constraints or noncompliance, but also in phenomena with low frequency. Small samples complicate causal evaluations for at least three reasons: (i) they are associated with greater sampling error, (ii) p-values based on standard tests are not trustworthy and the statistical power of these tests can be too low to detect significant program effects, (iii) the validity of parameter inference strongly depends on distributional assumptions. This paper proposes a simple approximation for the p-values to use in the regression analysis of treatment effects models with normal or nonnormal error distributions. The approximation is derived from recent developments in likelihood analysis and has a third-order distributional accuracy. Thus, for very small or medium-sized samples, the proposed method has remarkably higher accuracy compared to traditional ones that usually rely on normality or large samples. The method is then applied to aviation data to evaluate the impact of accidents on airfares, which is relevant to both airlines and insurance companies

ESSE 2017. Proceedings of the International Conference on Environmental Science and Sustainable Energy

Environmental science is an interdisciplinary academic field that integrates physical-, biological-, and information sciences to study and solve environmental problems. ESSE - The International Conference on Environmental Science and Sustainable Energy provides a platform for experts, professionals, and researchers to share updated information and stimulate the communication with each other. In 2017 it was held in Suzhou, China June 23-25, 2017

An overview of burst, buckling, durability and corrosion analysis of lightweight FRP composite pipes and their applicability

© 2019 Elsevier Ltd. All rights reserved.The main aim of this review article was to address the performance of filament wound fibre reinforced polymer (FRP) composite pipes and their critical properties, such as burst, buckling, durability and corrosion. The importance of process parameters concerning merits and demerits of the manufacturing methods was discussed for the better-quality performance. Burst analysis revealed that the winding angle of ±55° was observed to be optimum with minimum failure mechanisms, such as matrix cracking, whitening, leakage and fracture. The reduction of buckling effect was reported in case of lower hoop stress value in the hoop to axial stress ratio against axial, compression and torsion. A significant improvement in energy absorption was observed in the hybrid composite pipes with the effect of thermal treatment. However, the varying winding angle in FRP pipe fabrication was reported as an influencing factor affecting all the aforementioned properties. Almost 90% of the reviewed studies was done using E-glass/epoxy materials for the composite pipe production. By overcoming associated limitations, such as replacing synthetic materials, designing new material combinations and cost-benefit analysis, the production cost of the lightweight FRP composite pipes can be decreased for the real-time applications.Peer reviewe