Handling qualities requirements for control configured vehicles

The potential effects of fly by wire and control configured vehicle concepts on flying qualities are considered. Failure mode probabilities and consequences, controllability, and dynamics of highly augmented aircraft are among the factors discussed in terms of design criteria

Putting formal specifications under the magnifying glass: Model-based testing for validation

A software development process is effectively an abstract form of model transformation, starting from an end-user model of requirements, through to a system model for which code can be automatically generated. The success (or failure) of such a transformation depends substantially on obtaining a correct, well-formed initial model that captures user concerns. Model-based testing automates black box testing based on the model of the system under analysis. This paper proposes and evaluates a novel model-based testing technique that aims to reveal specification/requirement-related errors by generating test cases from a test model and exercising them on the design model. The case study outlined in the paper shows that a separate test model not only increases the level of objectivity of the requirements, but also supports the validation of the system under test through test case generation. The results obtained from the case study support the hypothesis that there may be discrepancies between the formal specification of the system modeled at developer end and the problem to be solved, and using solely formal verification methods may not be sufficient to reveal these. The approach presented in this paper aims at providing means to obtain greater confidence in the design model that is used as the basis for code generation

Macrophage-derived upd3 Cytokine causes impaired glucose homeostasis and reduced lifespan in drosophila fed a lipid-rich diet

Long-term consumption of fatty foods is associated with obesity, macrophage activation and inflammation, metabolic imbalance, and a reduced lifespan. We took advantage of Drosophila genetics to investigate the role of macrophages and the pathway(s) that govern their response to dietary stress. Flies fed a lipid-rich diet presented with increased fat storage, systemic activation of JAK-STAT signaling, reduced insulin sensitivity, hyperglycemia, and a shorter lifespan. Drosophila macrophages produced the JAK-STAT-activating cytokine upd3, in a scavenger-receptor (crq) and JNK-dependent manner. Genetic depletion of macrophages or macrophage-specific silencing of upd3 decreased JAK-STAT activation and rescued insulin sensitivity and the lifespan of Drosophila, but did not decrease fat storage. NF-κB signaling made no contribution to the phenotype observed. These results identify an evolutionarily conserved “scavenger receptor-JNK-type 1 cytokine” cassette in macrophages, which controls glucose metabolism and reduces lifespan in Drosophila maintained on a lipid-rich diet via activation of the JAK-STAT pathway

Thermochemistry of Grenfell Tower fire disaster: catastrophic effects of water as an 'extinguisher' in aluminium conflagrations

We review the thermochemistry of combustion reactions involved in the Grenfell Tower fire that occurred during the early hours of 14thJune 2017. London Fire Brigade (LFB), having advised all the occupants to stay in their apartments, attempted to extinguish the fire with water. The Grenfell Tower 24-storey block had recently been re-clad with an insulationto meet energy saving targets.It comprised an aluminum exterior façade, and a polymer composite thermal insulator ‘sandwich filler’, mainly polyethylene, with narrow air gaps inbetween polymer and aluminium sheets.The renovated window frames were also made of aluminum coated with a powdered polyester. Here, we highlight the scientific thermochemical reasonswhy water should never be used on aluminum fires; not least because a mixture of aluminium and water is a NASA rocket fuel! When the plastic insulation initially catches fire and burns with limited oxygen (O2 in air) to carbon(C), seen as an aerosol (black smoke) and black residue, the heat of reaction melts the aluminum(Al)and increases its fluidity and volatility, hence also its reactivity,whence it rapidly reacts with the carbon product of polymer combustion to form aluminum carbide (Al4C3). The heat of formation of Al4Cl3 is so great that it becomes white hot sparks like fireworks. At very high temperatures, both molten Al and Al4C3 aerosol react violently with water to give alumina fine dust aerosol(Al2O3)+ hydrogen (H2) gas and methane (CH4) gas, respectively, with white smoke and residues. These highly inflammable gases, with low spontaneous combustion temperatures, instantaneously react with the oxygen in air accelerating the fire out of control. Adding water to an aluminum fire is like adding “rocketfuel” to the existing flames. The timeline of events and photographic evidence corroborates this scientific explanation why a 4th-floor kitchen-appliance fire became a major tower-block inferno within 12minutes of applying water as a would-be extinguisher. A CO2-foam/powderextinguisher, as deployed in the aircraft industry against aluminum+plastic fires by smothering, might have contained the fire in its early stages. Thermochemistry of Grenfell Tower Fire Disasterinfo:eu-repo/semantics/publishedVersio

Thermodynamics of tower-block infernos: effects of water on aluminum fires

We review the thermodynamics of combustion reactions involved in aluminum fires in the light of the spate of recent high-profile tower-block disasters, such as the Grenfell fire in London 2017, the Dubai fires between 2010 and 2016, and the fires and explosions that resulted in the 9/11 collapse of the World Trade Center twin towers in New York. These fires are class B, i.e., burning metallic materials, yet water was applied in all cases as an extinguisher. Here, we highlight the scientific thermochemical reasons why water should never be used on aluminum fires, not least because a mixture of aluminum and water is a highly exothermic fuel. When the plastic materials initially catch fire and burn with limited oxygen (O2 in air) to carbon (C), which is seen as an aerosol (black smoke) and black residue, the heat of the reaction melts the aluminum (Al) and increases its fluidity and volatility. Hence, this process also increases its reactivity, whence it rapidly reacts with the carbon product of polymer combustion to form aluminum carbide (Al4C3). The heat of formation of Al4Cl3 is so great that it becomes white-hot sparks that are similar to fireworks. At very high temperatures, both molten Al and Al4C3 aerosol react violently with water to give alumina fine dust aerosol (Al2O3) + hydrogen (H2) gas and methane (CH4) gas, respectively, with white smoke and residues. These highly inflammable gases, with low spontaneous combustion temperatures, instantaneously react with the oxygen in the air, accelerating the fire out of control. Adding water to an aluminum fire is similar to adding "rocket fuel" to the existing flames. A CO2-foam/powder extinguisher, as deployed in the aircraft industry against aluminum and plastic fires by smothering, is required to contain aluminum fires at an early stage. Automatic sprinkler extinguisher systems should not be installed in tower blocks that are at risk of aluminum fires.info:eu-repo/semantics/publishedVersio

Elicitation of expert knowledge to inform object-based audio rendering to different systems

Object-based audio presents the opportunity to optimise audio reproduction for different listening scenarios. Vector base amplitude panning (VBAP) is typically used to render object-based scenes. Optimizing this process based on knowledge of the perception and practices of experts could result in significant improvements to the end user's listening experience. An experiment was conducted to investigate how content creators perceive changes in the perceptual attributes of the same content rendered to systems with different numbers of channels, and to determine what they would do differently to standard VBAP and matrix based downmixes to minimize these changes. Text mining and clustering of the content creators' responses revealed 6 general mix processes: the spatial spread of individual objects, EQ and processing, reverberation, position, bass, and level. Logistic regression models show the relationships between the mix processes, perceived changes in perceptual attributes, and the rendering method/speaker layout. The relative frequency of use for the different mix processes was found to differ between categories of audio object suggesting that any downmix rules should be object category specific. These results give insight into how object-based audio can be used to improve listener experience and provide the first template for doing this across different reproduction systems

The Influence of Cu-Additions on the Microstructure, Mechanical and Magnetic Properties of MnAl-C Alloys

Alloys of the form (Mn54Al44C2)100-xCux (with x = 0, 1, 2, 4 and 6) were produced by induction melting. After homogenisation and quenching, most of the alloys consist entirely of the retained ε-phase, except for x = 6, in which the κ-phase was additionally present. After subsequent annealing, the alloys with x ≤ 2 consist entirely of a Cu-doped, ferromagnetic τ-phase, whereas the alloys with x > 2 additionally contain the κ-phase. The polarisation of the alloys at an applied field of 14 T decreases with increasing Cu-content, which is attributed i) to the dilution of the magnetic moment of the τ-phase unit cell by the Cu atoms, which do not carry a magnetic moment, and ii) at higher Cu-contents, to the formation of the κ-phase, which has a much lower polarisation than the τ-phase and therefore dilutes the net polarisation of the alloys. The Curie temperature was not affected by the Cu-additions. The stress needed to die-upset the alloys with x ≤ 2 was similar to that of the undoped alloy, whereas it was much lower for x = 4 and 6, due to the presence of intergranular layers of the κ-phase. The extrinsic magnetic properties of alloys with x ≤ 2 were improved by die-upsetting, whereas decomposition of the τ-phase during processing had a deleterious effect on the magnetic properties for higher Cu-additions

Personalized object-based audio for hearing impaired TV viewers

Age demographics have led to an increase in the proportion of the population suffering from some form of hearing loss. The introduction of object-based audio to television broadcast has the potential to improve the viewing experience for millions of hearing impaired people. Personalization of object-based audio can assist in overcoming difficulties in understanding speech and understanding the narrative of broadcast media. The research presented here documents a Multi-Dimensional Audio (MDA) implementation of object-based clean audio to present independent object streams based on object category elicitation. Evaluations were carried out with hearing impaired people and participants were able to personalize audio levels independently for four object-categories using an on-screen menu: speech, music, background effects and foreground effects related to on-screen events. Results show considerable preference variation across subjects but indicate that expanding object-category personalization beyond a binary speech/non-speech categorization can substantially improve the viewing experience for some hearing impaired people