Effect of Out-Gassing on the Onset of Hypersonic Boundary Layer Transition

Prediction and control of the onset of transition and the associated variation in aerothermodynamic parameters in high-speed flows is key to optimize the performance and design of Thermal Protection Systems (TPS) of next-generation aerospace vehicles [1]. Boundary Layer Transition (BLT) characteristics can influence the surface heating budget determining the TPS thickness and consequently its weight penalty. Ablative heatshields are designed to alleviate the high heat flux at the surface through pyrolysis of their polymeric matrix and subsequent fiber ablation [2]. Pyrolysis leads to out-gassing and non-uniform ablation lead to surface roughness, both of which are known to influence the transition process. An ablator impacts BLT through three main routes: gas injecting into the boundary layer from the wall, changing the surface heat transfer due to wall-flow chemical reactions, and modifying surface roughness [3]. In preparation to Mars 2020 mission post-flight analysis, the predictive transition capability has been initiated toward hard-coupling porous material response analysis and aerothermal environment calculation

Collective directional movement and the perception of social cohesion

Stuart Wilson - ORCID 0000-0003-2119-5209 http://orcid.org/0000-0003-2119-5209Jamal K. Mansour - ORCID 0000-0001-7162-8493 https://orcid.org/0000-0001-7162-8493Replaced AM with VoR 09 Jan 2020We argue that perceivers associate collective directional movement – groups moving from one place to the next – with higher levels of social cohesion. Study 1 shows that pairs are rated as being more cohesive when described as engaging in directional movement compared to non-directional activities. Study 2 replicates this finding using film clips. Study 3 reveals that the proximity of directionally moving dyads is a better predictor of perceived cohesion than behavioural synchrony. Study 4 replicates the original finding and reveals that perceptions of common fate and shared goals both contribute to the effect, with the former having more predictive power than the latter. We suggest that collective directional movement is an invariant part of social environments and is utilised by perceivers to make inferences about social dynamics.https://doi.org/10.1111/bjso.1236159pubpub

Exploring live cloud migration on amazon EC2

Cloud users may decide to live migrate their virtual machines from a public cloud provider to another due to a lower cost or ceasing operations. Currently, it is not possible to install a second virtualization platform on public cloud infrastructure (IaaS) because nested virtualization and hardwareassisted virtualization are disabled by default. As a result, cloud users' VMs are tightly coupled to providers IaaS hindering live migration of VMs to different providers. This paper introduces LivCloud, a solution to live cloud migration. LivCloud is designed based on well-established criteria to live migrate VMs across various cloud IaaS with minimal interruption to the services hosted on these VMs. The paper discusses the basic design of LivCloud which consists of a Virtual Machine manager and IPsec VPN tunnel introduced for the first time within this environment. It is also the first time that the migrated VM architecture (64-bit & 32-bit) is taken into consideration. In this study, we evaluate the implementation of the basic design of LivCloud on Amazon EC2 C4 instance. This instance has a compute optimized instance and has high performance processors. In particular we explore three developed options. Theses options are being tested for the first time on EC2 to change the value of the EC2 instance's control registers. Changing the values of the registers will significantly help enable nested virtualization on Amazon EC2

Green Building Perception Matrix, A Theoretical Framework

Research has consistently shown that architects differ from the public in what they prefer in buildings. Today, as building design and construction evolve to more sustainability, some recent studies show that the overall level of satisfaction of occupants of green buildings still does not exceed the level of satisfaction in conventional structures. Satisfaction is typically measured, with Post Occupancy Evaluation, which gathers feedback from building occupants about aspects such as comfort, indoor air quality, and aesthetics. This raises some questions: Do people perceive green building design as consistent with their desire for sustainability? Do ratings of green buildings by systems such as LEED or BREAM affect the level of satisfaction of laypeople? Can owners and occupants of green buildings be considered as green consumers, who are attracted to green products because of their willingness to mitigate the impact of human activities on the environment? This article examines Peattie’s (2001) green purchase perception matrix as a means of understanding occupants’ perceptions of green-labeled buildings. An analytical approach has been taken to identify the influential factors, which are involved in this relationship. As a result, the authors propose a green building perception matrix that addresses the compromise that occupants must make in green buildings and the confidence that building systems are indeed making a difference environmentally. Understanding and using this matrix may help green building designers to improve the level of satisfaction of building’s owners and occupants. The discussion is critical for future research on how green building design attributes can be used as a catalyst for green consumption behavior