The current paper examined the relationship between frontal alpha asymmetry (FAA) and threatening face stimuli. Participants were presented with threatening faces, and this was compared to non-threatening (neutral) faces, on the assumption that the threatening faces would trigger a withdrawal motivation and a corresponding decrease in state FAA scores. The EEG data used in the present analysis was taken from an earlier study at the University of Skövde, consisting of twenty-eight participants with no reported current ongoing neurological or psychiatric illnesses, or epilepsy. Based on the paired samples t-test there was no significant statistical difference between participants’ FAA scores in the threatening and non-threatening conditions. The relatively small sample of the present study may be a contributing factor. Furthermore, threatening face images may elicit weaker responses than non-facial images such as threatening images of domestic violence or natural disasters. In the future, the field of FAA may benefit from investigating the connection between FAA and non-facial threatening and non-threatening images, instead of faces.

O desempenho dos pavimentos de concreto asfáltico depende das propriedades e proporções relativas dos seus principais componentes, ou seja, dos agregados minerais, do cimento asfáltico e do volume de vazios. O desempenho das misturas asfálticas de graduação densa é predominantemente influenciado pelas características de forma, angularidade e textura superficial dos agregados finos, que condicionam a estabilidade das misturas. O ensaio de Angularidade do Agregado Fino (FAA), adotado pelo Superpave para avaliar e quantificar a forma, a angularidade e a textura superficial das partículas, tem levantado muitas dúvidas quanto à sua adequabilidade. O objetivo deste trabalho é verificar se o ensaio FAA é capaz de classificar os agregados finos, identificando materiais com melhores condições para utilização em misturas asfálticas. Para tanto, são realizados, além de ensaios de angularidade do agregado fino, análise visual da forma, angularidade e textura superficial, ensaios de cisalhamento direto em amostras de agregado fino e ensaios Marshall em amostras de misturas asfálticas produzidas com diferentes agregados finos. Os resultados obtidos nas análises visuais indicam que o ensaio FAA não é capaz de separar os efeitos de angularidade e de forma das partículas. Os resultados dos ensaios de cisalhamento direto demonstram que um agregado fino com maior FAA não apresenta, necessariamente, uma maior resistência ao cisalhamento. Os resultados do ensaio Marshall também não demonstram correlação da estabilidade com os valores de FAA. Todos os resultados obtidos revelam que o ensaio FAA não é capaz de classificar adequadamente os agregados finos e, desta forma, não é capaz de identificar agregados que proporcionam misturas asfálticas com melhor desempenho / The performance of hot-mix asphalt (HMA) pavements depends on the properties and proportions of the major components, i.e., mineral aggregates, asphalt cement and air voids. The performance of dense asphalt mixtures is influenced mainly by fine aggregate characteristics, such as shape, angularity and surface texture. The Fine Aggregate Angularity test (FAA), adopted by Superpave to evaluate and quantify the shape, angularity and surface texture of fine aggregate particles, has lead a lot of doubts regarding its suitability. The objective of this work is to verify if the FAA test is really able to classify fine aggregates and identify the good ones to be used in asphalt mixtures. Thus, FAA test, visual analysis of shape, angularity and surface texture, direct shear test with samples of fine aggregates and Marshall test with samples of asphalt mixtures produced with different fine aggregates are performed. The results obtained in the visual analyses indicate that the FAA test is not able to separate the effects of angularity from the effects of shape. The results of the direct shear test demonstrate that a fine aggregate with a higher FAA doesn't present, necessarily, a larger shear strength. The values of the Marshall test doesn't demonstrate correlation between Marshall stability and FAA values. All the results show that the FAA test is not able to classify fine aggregates appropriately and, therefore, is unable to identify aggregates that provide mixtures with better performance

O desempenho dos pavimentos de concreto asfáltico depende das propriedades e proporções relativas dos seus principais componentes, ou seja, dos agregados minerais, do cimento asfáltico e do volume de vazios. O desempenho das misturas asfálticas de graduação densa é predominantemente influenciado pelas características de forma, angularidade e textura superficial dos agregados finos, que condicionam a estabilidade das misturas. O ensaio de Angularidade do Agregado Fino (FAA), adotado pelo Superpave para avaliar e quantificar a forma, a angularidade e a textura superficial das partículas, tem levantado muitas dúvidas quanto à sua adequabilidade. O objetivo deste trabalho é verificar se o ensaio FAA é capaz de classificar os agregados finos, identificando materiais com melhores condições para utilização em misturas asfálticas. Para tanto, são realizados, além de ensaios de angularidade do agregado fino, análise visual da forma, angularidade e textura superficial, ensaios de cisalhamento direto em amostras de agregado fino e ensaios Marshall em amostras de misturas asfálticas produzidas com diferentes agregados finos. Os resultados obtidos nas análises visuais indicam que o ensaio FAA não é capaz de separar os efeitos de angularidade e de forma das partículas. Os resultados dos ensaios de cisalhamento direto demonstram que um agregado fino com maior FAA não apresenta, necessariamente, uma maior resistência ao cisalhamento. Os resultados do ensaio Marshall também não demonstram correlação da estabilidade com os valores de FAA. Todos os resultados obtidos revelam que o ensaio FAA não é capaz de classificar adequadamente os agregados finos e, desta forma, não é capaz de identificar agregados que proporcionam misturas asfálticas com melhor desempenho / The performance of hot-mix asphalt (HMA) pavements depends on the properties and proportions of the major components, i.e., mineral aggregates, asphalt cement and air voids. The performance of dense asphalt mixtures is influenced mainly by fine aggregate characteristics, such as shape, angularity and surface texture. The Fine Aggregate Angularity test (FAA), adopted by Superpave to evaluate and quantify the shape, angularity and surface texture of fine aggregate particles, has lead a lot of doubts regarding its suitability. The objective of this work is to verify if the FAA test is really able to classify fine aggregates and identify the good ones to be used in asphalt mixtures. Thus, FAA test, visual analysis of shape, angularity and surface texture, direct shear test with samples of fine aggregates and Marshall test with samples of asphalt mixtures produced with different fine aggregates are performed. The results obtained in the visual analyses indicate that the FAA test is not able to separate the effects of angularity from the effects of shape. The results of the direct shear test demonstrate that a fine aggregate with a higher FAA doesn't present, necessarily, a larger shear strength. The values of the Marshall test doesn't demonstrate correlation between Marshall stability and FAA values. All the results show that the FAA test is not able to classify fine aggregates appropriately and, therefore, is unable to identify aggregates that provide mixtures with better performance

No description available.

The aviation industry aims to reduce its environmental impact through innovation and research. The usage of composite materials for multiple primary structures represents one such measure. Several alternative fuels were approved and used along with the Federal Aviation Administration (FAA). These alternative fuels are produced from wastes and biomasses. Some alternative fuels were initially only approved as drop-in fuels, meaning they must be blended with conventional fuels to operate. Fuel tanks are usually embedded into the wing structure, which is mainly made of composite materials. These composites tend to absorb fluids it encounters through their matrix phase. The absorption behavior of conventional fuels by composite materials is well documented, while alternative fuels, blended or pure, are not as widely reported. The effects of four alternative fuel blends on aerospace-grade composites were investigated and compared with the conventional fuel Jet A. No significant differences were found in weight gain. The thermomechanical properties changes were also studied, with no difference between the alternative fuel blends and the conventional fuel. Additionally, model fluids with similar chemical structures as alternative fuels were used. The uptake of these model fluids was studied cyclically and compared with Jet A and one aromatic fluid. Small differences were seen in the weight gain results, primarily due to the type of model fluids used. Also, the thermomechanical properties showed no differences between these model fluids, Jet A and the pure aromatic fluid. This means that the slight differences in weight gain did not affect the changes in properties. From the results obtained, the alternative fuels blended, and the model fluids showed no differences in effects on the thermomechanical properties versus Jet A. This implies that similar effects are expected from either type of fluids used. Finite element analysis was used to model fluid’s diffusion in composite materials using different material parameters. The parameters were fiber packing, arrangement and permeability. Each parameters impacted the equilibrium uptake and the diffusion rate differently.

Unmanned aerial systems (UASs) have a great potential to enhanced situational awareness in public safety operations. Many UASs operating in the same airspace can cause mid-air collisions. NASA and the FAA are developing a UAS traffic management (UTM) system, which could be used in public safety operations to manage the UAS airspace. UTM relies on an existing communication backhaul, however natural disasters may disrupt existing communications infrastructure or occur in areas where no backhaul exists. This thesis outlines a robust communications alternative that interfaces a fleet of UASs with a UTM service supplier (USS) over a mesh network. Additionally, this thesis outlines an algorithm for vehicle-to-vehicle discovery and communication over the mesh network.

No description available.

A covariant Wigner-Weyl quantization formalism on the manifold that uses pseudo-differential operators is proposed. The asymptotic product formula that leads to the symbol calculus in the presence of gauge and gravitational fields is presented. The new definition is used to get covariant differential operators from momentum polynomial symbols. A covariant Wigner function is defined and shown to give gauge-invariant results for the Landau problem. An example of the covariant Wigner function on the 2-sphere is also included.

Master’s thesis deals with problems of maintenance of small transport aircraft with application MSG-3 methodology and maintenance plan development. It is aimed at systems and powerplant maintenance. This method is applied on L-410UVP-E20 aircraft. Other parts of this work are assessment of recent situation in maintenance of airplanes, used approaches to maintenance, methods and documentation for maintenance. Last part of this work is practical example of MSG-3 process on assign item and its interpretation.

There is much dialogue in the global aviation industry about Safety Management Systems (SMS) and how it should be integrated across all domains of the industry including aircraft design, production, flight operations, overhaul and maintenance, suppliers, service providers, airports, and so forth (Johnson, 2012). Regulators have made significant progress in recent years to implement ICAO’s SMS into airlines, albeit as a required or recommended practice. More recently the regulators are seeking to implement SMS into the aircraft manufacturing and aircraft maintenance domains. This research reviewed regulatory publications from multiple countries to assess the technical makeup of SMS, and understand what regulators are requiring, or recommending, and when. It was found that global regulators accept the ICAO published definition of SMS, but different regulators have varying approaches regarding implementation. However, they are consistent in initially targeting airlines for SMS implementation. SMS comments range from “The best thing since sliced bread” to “Worst thing since the creation of the FAA; I don’t need anyone telling me what’s safe when I already know it; waste of time and money”. This investigation experimented with field tests to connect the engineering, production and airline domains into one ICAO SMS model. Results indicate that because the different domains are risk-specific, the application of one safety risk management model to all domains is not viable. The SMS model applies to airlines because airlines’ primary risk is about operational safety. Aircraft production and maintenance is about production risk – therefore the risk model must be centric to process risk. Field test 3 tailored the ICAO SMS risk architecture to assess and mitigate process risk as applicable to the aircraft manufacturing and maintenance. Although the SMS architecture was usable, the content and focus was significantly adjusted to be production process-risk centric, to the point where the term “SMS’ was deemed out of place. The resulting model was therefore named Production Risk Management System (PRMS). Following the emergence of PRMS from field tests, this investigation reviewed industry, research and regulatory arguments for and against SMS in the airline industry, and correlated those arguments with the benefits and non-benefits of PRMS for the manufacturing and aircraft maintenance domains. The researcher advocates PRMS as a viable model that meets ICAO SMS-like architecture for aircraft production and maintenance. Methods were identified for developing and implementing PRMS, and for evaluating its ROI. If and when “SMS” is truly mandated in these domains, the researcher proposes PRMS as a viable model that should be considered. Furthermore, the researcher proposes that PRMS can be an effective production risk management system that can enhance the organization’s existing QMS, regardless of “SMS” regulations.