Fluid structure interaction of a two-dimensional membrane in a flow with a pressure gradient with application to convertible car roofs

Original article can be found at : http://www.sciencedirect.com/ Copyright ElsevierThe flow-induced deformation of a membrane in a flow with a pressure gradient is studied. The investigation focuses on the deformation of aerodynamically loaded convertible car roofs. A computational methodology is developed with a line-element structural model that incorporates initial slackness of the flexible roof material. The computed flow–structure interaction yields stable solutions, the flexible roof settling into static equilibrium. The interaction converges to a static deformation within 1% difference in the displacement variable after three iterations between fluid and structural codes. Reasonably accurate predictions, to within 7%, are possible using only a single iteration between the fluid and the structural codes for the model problem studied herein. However, the deformation results are shown to be highly dependent on the physical parameters that are used in the calculation. Accurate representation of initial geometry, material properties and slackness should be found before the predictive benefits of the fluid–structure computations are sought. The iterative methodology overcomplicates the computation of deformation for the relatively small displacements encountered for the model problem studied herein. Such an approach would be better suited to applications with large amplitude displacements such as those encountered in sail design or deployment of a parachute.Peer reviewedFinal Accepted Versio

An Anatomy Based Health Education Curriculum Taught by Medical Students May Improve High School Students Health Knowledge

To date, few high school based interventions have been shown to have lasting effects on adolescents\u27 health behaviors. The need for health interventions targeting adolescents is underscored by data showing that several health behaviors with significant short and long term adverse effects begin in early adolescence and become progressively more prevalent toward late adolescence. This project tested the efficacy of a novel anatomy based health education curriculum at increasing health knowledge. The course was taught by first year Yale medical students. The curriculum placed emphasis on nutrition, physical activity and infectious disease. Forty Juniors from Career High School visited Yale\u27s anatomy lab once every two weeks for ten hour-long sessions. In addition to visits to the anatomy lab, students completed two class projects, one covered nutrition and the other focused on exercise. Four additional sessions at Career High School were dedicated to the class projects. Pre and post test analysis showed an improvement in health knowledge with a thirteen percentage point improvement on a standardized health knowledge survey. The students\u27 performance was compared to a control cohort of thirty-one students who were not exposed to the curriculum. Students exposed to the curriculum had a nineteen percentage point advantage compared to control students who had not been exposed. Curriculum efficacy as demonstrated by this small cohort validate further testing with larger cohorts and more vigorous controls as well as separate testing to measure changes in health behavior attributable to curriculum exposure

Cavity-free nondestructive detection of a single optical photon

Detecting a single photon without absorbing it is a long standing challenge in quantum optics. All experiments demonstrating the nondestructive detection of a photon make use of a high quality cavity. We present a cavity free scheme for nondestructive single-photon detection. By pumping a nonlinear medium we implement an inter-field Rabi-oscillation which leads to a ?pi phase shift on weak probe coherent laser field in the presence of a single signal photon without destroying the signal photon. Our cavity-free scheme operates with a fast intrinsic time scale in comparison with similar cavity-based schemes. We implement a full real-space multimode numerical analysis of the interacting photonic modes and confirm the validity of our nondestructive scheme in the multimode case.Comment: 4 figures, 5 page

Geršgorin and Beyond•••

Eigenvalues are useful in various areas of mathematics, such as in testing the critical values of a multi variable function to see if it is a local extrema. One of the more common ways to define eigenvalues is: Definition (1): Given that A is an n by n matrix, λ is an eigenvalue of A if and only if det(A - λIn) = 0. Any nonzero vector in Null(A - λI) is called an eigenvector associated with λ

Achieving continuous improvement through self-assessment

In 2007 the UK Office of Government Commerce was mandated to carry out Procurement Capability Reviews (PCR) across the 16 top spending UK Government Departments. Since then, this programme has evolved into a self assessment based approach which is markedly different from the original approach. Will the move from a centre-led strategic review of procurement capability to a department-led model based on self assessment continue to strengthen and improve procurement capability across Central Civil Government? OGC is currently working with UK Government Departments to carry out their PCRs using a self-assessment tool which incorporates qualitative and quantitative measures. Results are generated based on a capability maturity model. The results are assured independently. OGC expectations are that tangible and measurable capability improvements will be realised when departments embed the self-assessment model and implement the findings as part of a continuous improvement regime. This paper is a case study, using some relevant literature to reflect on past and possible future development of the PCR self assessment scheme

Raspberry Pi driven digital signage

Loughborough University makes extensive use of digital signage to display rapidly changing information to its staff, students and visitors. Within the library, digital signage displays show PC availability, study and meeting room bookings, IT support information and details of forthcoming events. To drive the displays small, inexpensive and low powered Raspberry Pi computers are used. The low cost and ease of use of the Raspberry Pi based solution has allowed the Library to have far more displays in use than would otherwise be possible, which provides for an enhanced user experience in the building. This paper describes how Raspberry Pi's can be used to drive displays, shows some of the cost savings that can be made and looks at some potential future applications of cheap, digital signage

Evaluating possible uses of a Raspberry Pi in an academic library environment

Loughborough University's Library Systems Team investigated two potential uses for Raspberry Pis. The first use to be identified for investigation was using the Raspberry Pi as a replacement for the existing OPAC hardware. While it met a majority of the requirements there were issues with the responsiveness to user input at certain times. The second use for Raspberry Pis investigated was to provide a number of digital signs to display details about resource bookings and the availability of PCs in IT labs around campus. The Raspberry Pi demonstrated that it was ideally suited to this task

Nonlinear Waves in Solid Continua with Finite Deformation

This work considers initiation of nonlinear waves, their propagation, reflection, and their interactions in thermoelastic solids and thermoviscoelastic solids with and without memory. The conservation and balance laws constituting the mathematical models are derived for finite deformation and finite strain using second Piola-Kirchoff stress tensor and Green's strain tensor. The constitutive theories for thermoelastic solids express the second Piola-Kirchoff stress tensor as a linear function of the Green's strain tensor. In the case of thermoviscoelastic solids without memory, the constitutive theory for deviatoric second Piola-Kirchoff stress tensor consists of a first order rate theory in which the deviatoric second Piola-Kirchoff stress tensor is a linear function of the Green's strain tensor and its material derivative. For thermoviscoelastic solids with memory, the constitutive theory for deviatoric second Piola-Kirchoff stress tensor consists of a first order rate theory in which the material derivative of the deviatoric second Piola-Kirchoff stress is expressed as a linear function of the deviatoric second Piola-Kirchoff stress, Green's strain tensor, and its material derivative. For thermoviscoelastic solids with memory, the constitutive theory for deviatoric second Piola-Kirchoff stress tensor consists of a first order rate theory in which the material derivative of the deviatoric second Piola-Kirchoff stress is expressed as a linear function of the deviatoric second Piola-Kirchoff stress, Green's strain tensor, and its material derivative. Fourier heat conduction law with constant conductivity is used as the constitutive theory for heat vector. The mathematical models are derived using conservation and balance laws. Alternate forms of the mathematical models are presented and their usefulness is illustrated in the numerical studies of the model problems with different boundary conditions. Nondimensionalized mathematical models are used in the computations of the numerical solutions of the model problems. All numerical studies are performed using space-time variationally consistent finite element formulations derived using space-time residual functionals in which the second variation of the residuals is neglected in the second variation of the residual functional and the non-linear equations resulting from the first variation of the residual functional are solved using Newton's Linear Method (Newton-Raphson method) with line search. Space-time local approximations are considered in higher order scalar product spaces that permit desired order of global differentiability in space and time. Extensive numerical studies are presented for different boundary conditions. Computed results for non-linear wave propagation, reflection, and interaction are compared with linear wave propagation to demonstrate significant differences between the two, the importance of the nonlinear wave propagation over linear wave propagation as well as to illustrate the meritorious features of the mathematical models and the space-time variationally consistent space-time finite element process with time marching in obtaining the numerical solutions of the evolutions