Evaluation of a large capacity heat pump concept for active cooling of hypersonic aircraft structure

Results of engineering analyses assessing the conceptual feasibility of a large capacity heat pump for enhancing active cooling of hypersonic aircraft structure are presented. A unique heat pump arrangement which permits cooling the structure of a Mach 6 transport to aluminum temperatures without the aid of thermal shielding is described. The selected concept is compatible with the use of conventional refrigerants, with Freon R-11 selected as the preferred refrigerant. Condenser temperatures were limited to levels compatible with the use of conventional refrigerants by incorporating a unique multipass condenser design, which extracts mechanical energy from the hydrogen fuel, prior to each subsequent pass through the condenser. Results show that it is technically feasible to use a large capacity heat pump in lieu of external shielding. Additional analyses are required to optimally apply this concept

Improved prediction of laminar leading edge separation

Research was conducted to provide a definite criterion for the prediction of the bubble burst on airfoils typical of those used for fighter wings. The approach taken was to correlate existing airfoil bubble burst data using various parameters at the laminar separation point. The method due to Weber was modified to provide a continuous analytic solution for the velocity distribution around the airfoil leading edge. Coupling the modified Weber method with the Stratford laminar separation prediction method leads to a universal chart giving the conditions at separation as a function of stagnation location and leading edge radius. Application of the combined method to available two-dimensional airfoil data resulted in an empirical criterion presenting the limiting local velocity gradient at separation as a function of the boundary layer momentum thickness at separation for bubble burst. The correlation leads as well to the qualitative explanation of two types of laminar stall: thin airfoil and leading edge. The validity of the correlation is demonstrated by predicting the lift coefficient and angle of attack for stall on airfoils with leading edge or trailing edge flaps

Compressive behavior of titanium alloy skin-stiffener specimens selectively reinforced with boron-aluminum composite

A method of selectively reinforcing a conventional titanium airframe structure with unidirectional boron-aluminum composite attached by brazing was successfully demonstrated in compression tests of short skin-stiffener specimens. In a comparison with all-titanium specimens, improvements in structural performance recorded for the composite-reinforced specimens exceeded 25 percent on an equivalent-weight basis over the range from room temperature to 700 K (800 F) in terms of both initial buckling and maximum strengths. Performance at room temperature was not affected by prior exposure at 588 K (600 F) for 1000 hours in air or by 400 thermal cycles between 219 K and 588 K (-65 F and 600 F). The experimental results were generally predictable from existing analytical procedures. No evidence of failure was observed in the braze between the boron-aluminum composite and the titanium alloy

Fathers and substance misuse: a literature review

Purpose To review the following research questions from the available literature: • What evidence is there to suggest that substance misuse specifically by fathers (including alcohol and other drugs) causes wider harms, including child welfare concerns? • How do professionals respond specifically to substance misuse by fathers? • Do interventions aimed at parental substance misuse (particularly in the UK) include both mothers and fathers and if so how? Design/methodology/approach Scoping literature review, identifying 34 papers, (including scoping reviews published in 2006 and 2008 and six cited papers, covering the period 1990 – 2005), and 26 additional studies published between 2002 and 2020. Findings The review is organized into six themes: 1) Negative impact of men’s substance misuse problems on their parenting behaviours 2) Quality of the relationship between parents is affected by substance misuse of the fathers, in turn affecting the parenting behaviour and outcomes for child/ren 3) Importance to fathers of their fathering role (for example as financial provider) 4) Difficulties fathers may face in developing their fathering role 5) Sidelining of the fathering role in substance misuse services 6) Professionals tending to focus on the mother’s role in parenting inventions and services Originality The review focuses on fathers and substance misuse, an under-researched field within the wider contexts of fathering research and research into parental substance misus

Public health participation in alcohol licensing decisions in England: the importance of navigating "contested space"

The Police Reform and Social Responsibility Act of 2011, added ‘health bodies’ as responsible authorities in licensing and, in practice, Directors of Public Health undertook this role. Despite this legislation facilitating the inclusion of public health in partnerships around licensing in England, wide variations in involvement levels by Public Health professionals persist This article is based on the findings from interviews that explored the experiences of public health professionals engaging with local established partnerships around alcohol licensing. Qualitative data were collected through twenty-one interviews in a purposeful sample of London boroughs. These data were combined with analyses of relevant area documentation and observations of fourteen licensing sub-committee meetings in one London borough over a seven-month period. Thematic analysis of all data sources was conducted to identify emerging themes. This study highlighted the importance of successful navigation of the ‘contested space’ (Hunter and Perkins, 2014) surrounding both public health practice and licensing partnerships. In some instances, contested spaces were successfully negotiated and public health departments achieved an increased level of participation within the partnership. Ultimately, improvements in engagement levels of public health teams within licensing could be achieved. The paper explores a neglected aspect of research around partnership working and highlights the issues arising when a new partner attempts to enter an existing partnership

Design of linear and nonlinear control systems via state variable feedback, with applications in nuclear reactor control

Linear and nonlinear control systems via state variable feedback with applications in nuclear reactor contro

Thermal design for areas of interference heating on actively cooled hypersonic aircraft

Numerous actively cooled panel design alternatives for application in regions on high speed aircraft that are subject to interference heating effects were studied. Candidate design concepts were evaluated using mass, producibility, reliability and inspectability/maintainability as figures of merit. Three design approaches were identified as superior within certain regimes of the matrix of design heating conditions considered. Only minor modifications to basic actively cooled panel design are required to withstand minor interference heating effects. Designs incorporating internally finned coolant tubes to augment heat transfer are recommended for moderate design heating conditions. At severe heating conditions, an insulated panel concept is required

Mothers' voices: hearing and assessing the contributions of 'birth mothers' to the development of social work interventions and family support

This paper focuses on interviews with ‘birth mothers’ who experienced successive losses of their children to public care in one local area of London, England. Interviews were conducted during a project partnership between a London borough and university staff, aiming to provide a localised, pilot support initiative which responded to mothers’ viewpoints. To ‘hear’ mothers’ own voices more clearly, we analysed interview transcripts using a methodology which separates out elements of how the interviewee tells her story, how she speaks about herself and about her relationships, taking into account surrounding social complexities and researchers’ reactions to the story. To explain how professionals could subsequently draw upon these ‘mothers’ voices’ for a pilot support initiative, we identify some key messages for professionals from these interviews, including: women wanting clear and honest communication between themselves and workers, and between staff; women often feeling ‘let down’ by professional procedures and court processes that were moving too fast for them to keep up; women wanting to be treated with more respect. Women respected some professionals but not others and this seemed to relate partly to personalities. Some mothers experienced being ‘left alone’ or ‘abandoned’ to deal with the aftermath of children’s removal and/or adoption

Current driven magnetization dynamics in helical spin density waves

A mechanism is proposed for manipulating the magnetic state of a helical spin density wave using a current. In this paper, we show that a current through a bulk system with a helical spin density wave induces a spin transfer torque, giving rise to a rotation of the order parameter.The use of spin transfer torque to manipulate the magnetization in bulk systems does not suffer from the obstacles seen for magnetization reversal using interface spin transfer torque in multilayered systems. We demonstrate the effect by a quantitative calculation of the current induced magnetization dynamics of Erbium. Finally we propose a setup for experimental verification.Comment: In the previous version of this paper was a small numerical mistake made when evaluating equation 3 and 9. The number of digits given in the calculation of the torque current tensor is reduced to better represent the accuracy of the calculation. A slightly modified paper have been published in Phys. Rev. Lett. 96, 256601 (2006) 4 pages 3 figure

Eulerian spectral closures for isotropic turbulence using a time-ordered fluctuation-dissipation relation

Procedures for time-ordering the covariance function, as given in a previous paper (K. Kiyani and W.D. McComb Phys. Rev. E 70, 066303 (2004)), are extended and used to show that the response function associated at second order with the Kraichnan-Wyld perturbation series can be determined by a local (in wavenumber) energy balance. These time-ordering procedures also allow the two-time formulation to be reduced to time-independent form by means of exponential approximations and it is verified that the response equation does not have an infra-red divergence at infinite Reynolds number. Lastly, single-time Markovianised closure equations (stated in the previous paper above) are derived and shown to be compatible with the Kolmogorov distribution without the need to introduce an ad hoc constant.Comment: 12 page