Analytical study of interior noise control by fuselage design techniques on high-speed, propeller-driven aircraft

The acoustical treatment mass penalties required to achieve an interior noise level of 80 dBA for high speed, fuel efficient propfan-powered aircraft are determined. The prediction method used is based on theory developed for the outer shell dynamics, and a modified approach for add-on noise control element performance. The present synthesis of these methods is supported by experimental data. Three different sized aircraft are studied, including a widebody, a narrowbody and a business sized aircraft. Noise control penalties are calculated for each aircraft for two kinds of noise control designs: add-on designs, where the outer wall structure cannot be changed, and advanced designs where the outer wall stiffness level and the materials usage can be altered. For the add-on designs, the mass penalties range from 1.7 to 2.4 percent of the takeoff gross weight (TOGW) of the various aircraft, similar to preliminary estimates. Results for advanced designs show significant reductions of the mass penalties. For the advanced aluminum designs the penalties are 1.5% of TOGW, and for an all composite aircraft the penalties range from 0.74 to 1.4% of TOGW

Ligand-induced closure of inward rectifier Kir6.2 channels traps spermine in the pore

Small organic amines block open voltage-gated K(+) channels and can be trapped by subsequent closure. Such studies provide strong evidence for voltage gating occurring at the intracellular end of the channel. We engineered the necessary properties (long block times with unblock kinetics comparable to, or slower than, the kinetics of gating) into spermine-blocked, ATP-gated (N160D,L157C) mutant K(ATP) channels, in order to test the possibility of “blocker trapping” in ligand-gated Kir channels. Spermine block of these channels is very strongly voltage dependent, such that, at positive voltages, the off-rate of spermine is very low. A brief pulse to negative voltages rapidly relieves the block, but no such relief is observed in ATP-closed channels. The results are well fit by a simple kinetic model that assumes no spermine exit from closed channels. The results incontrovertibly demonstrate that spermine is trapped in channels that are closed by ATP, and implicate the M2 helix bundle crossing, or somewhere lower, as the probable location of the gate

The PELskin project—part I: fluid–structure interaction for a row of flexible flaps: a reference study in oscillating channel flow

Previous studies of flexible flaps attached to the aft part of a cylinder have demonstrated a favourable effect on the drag and lift force fluctuation. This observation is thought to be linked to the excitation of travelling waves along the flaps and as a consequence of that, periodic shedding of the von Kármán vortices is altered in phase. A more general case of such interaction is studied herein for a limited row of flaps in an oscillating flow; representative of the cylinder case since the transversal flow in the wake-region shows oscillating character. This reference case is chosen to qualify recently developed numerical methods for the simulation of fluid–structure interaction in the context of the EU funded ‘PELskin’ project. The simulation of the two-way coupled dynamics of the flexible elements is achieved via a structure model for the flap motion, which was implemented and coupled to two different fluid solvers via the immersed boundary method. The results show the waving behaviour observed at the tips of the flexible elements in interaction with the fluid flow and the formation of vortices in the gaps between the flaps. In addition, formation of vortices upstream of the leading and downstream of the trailing flap is seen, which interact with the formation of the shear-layer on top of the row. This leads to a phase shift in the wave-type motion along the row that resembles the observation in the cylinder case

Inter-model comparison of global hydroxyl radical (OH) distributions and their impact on atmospheric methane over the 2000–2016 period

The modeling study presented here aims to estimate how uncertainties in global hydroxyl radical (OH) distributions, variability, and trends may contribute to resolving discrepancies between simulated and observed methane (CH4) changes since 2000. A multi-model ensemble of 14 OH fields was analyzed and aggregated into 64 scenarios to force the offline atmospheric chemistry transport model LMDz (Laboratoire de Meteorologie Dynamique) with a standard CH4 emission scenario over the period 2000–2016. The multi-model simulated global volume-weighted tropospheric mean OH concentration ([OH]) averaged over 2000–2010 ranges between 8:7*10^5 and 12:8*10^5 molec cm-3. The inter-model differences in tropospheric OH burden and vertical distributions are mainly determined by the differences in the nitrogen oxide (NO) distributions, while the spatial discrepancies between OH fields are mostly due to differences in natural emissions and volatile organic compound (VOC) chemistry. From 2000 to 2010, most simulated OH fields show an increase of 0.1–0:3*10^5 molec cm-3 in the tropospheric mean [OH], with year-to-year variations much smaller than during the historical period 1960–2000. Once ingested into the LMDz model, these OH changes translated into a 5 to 15 ppbv reduction in the CH4 mixing ratio in 2010, which represents 7%–20% of the model-simulated CH4 increase due to surface emissions. Between 2010 and 2016, the ensemble of simulations showed that OH changes could lead to a CH4 mixing ratio uncertainty of > 30 ppbv. Over the full 2000–2016 time period, using a common stateof- the-art but nonoptimized emission scenario, the impact of [OH] changes tested here can explain up to 54% of the gap between model simulations and observations. This result emphasizes the importance of better representing OH abundance and variations in CH4 forward simulations and emission optimizations performed by atmospheric inversions

The PELskin project: part II—investigating the physical coupling between flexible filaments in an oscillating flow

The fluid-structure interaction mechanisms of a coating composed of flexible flaps immersed in a periodically oscillating channel flow is here studied by means of numerical simulation, employing the Euler-Bernoulli equations to account for the flexibility of the structures. A set of passively actuated flaps have previously been demonstrated to deliver favourable aerodynamic impact when attached to a bluff body undergoing periodic vortex shedding. As such, the present configuration is identified to provide a useful test-bed to better understand this mechanism, thought to be linked to experimentally observed travelling waves. Having previously validated and elucidated the flow mechanism in Paper 1 of this series, we hereby undertake a more detailed analysis of spectra obtained for different natural frequency of structures and different configurations, in order to better characterize the mechanisms involved in the organized motion of the structures. Herein, this wave-like behaviour, observed at the tips of flexible structures via interaction with the fluid flow, is characterized by examining the time history of the filaments motion and the corresponding effects on the fluid flow, in terms of dynamics and frequency of the fluid velocity. Results indicate that the wave motion behaviour is associated with the formation of vortices in the gaps between the flaps, which itself are a function of the structural resistance to the cross flow. In addition, formation of vortices upstream of the leading and downstream of the trailing flap is seen, which interact with the formation of the shear-layer on top of the row. This leads to a phase shift in the wave-type motion along the row that resembles the observation in the cylinder case

Teacher practice and the pre-crime space: prevent, safeguarding and teacher engagement with extremism and radicalisation

School involvement in government initiatives to combat radicalisation is an international phenomena, in the UK government has focused on the role of the teacher in detecting radicalisation through the Teachers’ Standards of 2012, the Counter Terrorism Act 2015 and the activation of Prevent in 2011. The Prevent Duty has been described as a geographical pre-crime space characterised by surveillance, risk, fear and the notion of the pre-criminal. This article explores the way teachers understand their practice in this pre-crime space. The data discussed in this study is part of a larger study that interrogates the way teachers approach the teaching of Islam in schools. This article reports on a series of dialogical interviews and analyses the way 57 teachers with a particular responsibility for Religious Education have negotiated this new role. It argues that teachers commonly situate their practice in relation to Prevent in the context of a safeguarding agenda and that most legitimise their role through the employment of a discourse of vulnerability. The research suggests that the ways teachers approach issues of extremism in the classroom is in part informed by their existing views on racism, social class and political ideologies

Bioactive ceramic-reinforced composites for bone augmentation

Biomaterials have been used to repair the human body for millennia, but it is only since the 1970s that man-made composites have been used. Hydroxyapatite (HA)-reinforced polyethylene (PE) is the first of the ‘second-generation’ biomaterials that have been developed to be bioactive rather than bioinert. The mechanical properties have been characterized using quasi-static, fatigue, creep and fracture toughness testing, and these studies have allowed optimization of the production method. The in vitro and in vivo biological properties have been investigated with a range of filler content and have shown that the presence of sufficient bioactive filler leads to a bioactive composite. Finally, the material has been applied clinically, initially in the orbital floor and later in the middle ear. From this initial combination of HA in PE other bioactive ceramic polymer composites have been developed

Islam as educational knowledge: challenges and barriers to the development of a Religion and Worldviews approach to teaching Islam in schools

This article discusses the way teachers in primary and secondary schools in England engaged with a project to develop a Worldviews approach to Islam in the RE classroom. The project identified challenges and barriers to the teaching of Worldviews that were demonstrated by some teachers’ unwillingness to engage with knowledge and curriculum content that they believed to be illegitimate or controversial. The authors use Basil Bernstein’s idea of educational knowledge to explore the way teachers made decisions about what pupils should be permitted to learn about and what should be ignored in relation to Islam

School leadership and the civic nationalist turn: Towards a typology of leadership styles employed by head teachers in their enactment of the Prevent Duty and the promotion of fundamental British values

British schools are teeming with cultural richness and have long been at the heart of a celebration of heritage. However, the riots in the north of England in 2001 exposed fractures in community cohesion, a loss of economic opportunity for marginalised groups and a rise in far-right activity. The London bombings of 2005 revealed deep fault lines across communities and by 2012 the government had implemented the ‘Hostile Environment’ and Immigration Laws of 2014 and 2016 which saw citizens assume the mantle of ‘border enforcer.’ The Windrush scandal of 2017 was an expression of this environment, and coupled with a resurgent nationalism, the UK voted to leave the EU. Schools, nested within diverse communities across the country, negotiate societal issues and tensions in the quotidian spaces of the school day and head teachers, charged with ensuring the Prevent Duty is enacted and British values promoted, determine the ethos and approach of their respective schools. Drawing on literature from school leadership, this research engages with head teachers in schools in England to explore the leadership styles they employ when enacting the requirements of the Counter-Terrorism and Security Act 2015 (Home Office, 2015) and the Teachers’ Standards (DfE, 2012) and navigating the civic nationalist turn