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This report describes the research activities conducted at the University of Manchester in this project. A comprehensive literature survey of the relevant phenomena and subsequent interactions is presented along with a description of the wind tunnel facility calibration. Experimental techniques and methodologies are discussed, including reference to the range of their applicability in the campaign. Model designs, experimental setup, and preliminary analysis of the flow field are presented. The following techniques have already been used in the experimental programme: high speed schlieren photography, infrared thermography and force measurements taken from a three-component balance., The original document contains color images.

This report presents investigations performed on the hypersonic flow-field over a flat plate with and without thermal induced bump in the University of Manchester hypersonic blowdown wind tunnel HSST at Mach no. 5.0 and free-stream Reynolds no. 6.2x106 to 11.6x106 per metre. Experiments were conducted with air as the test gas. The report consists of two parts: The first part deals with the experiments using a microheater coil of 16mm diameter to simulate the thermal bump. Quantitative heat transfer measurements were performed using IR-thermography. The surface pressure measurements using pressure-sensitive paints are also presented. Since IR-thermography has been widely used to measure surface temperature, a brief description of heat flux calculation based on the surface temperature history is given. The theoretical predictions of heat transfer coefficient over the flat plate are also presented. Emphasis is put on the quantitative heat transfer rate measurements. Tests using pressure-sensitive paints are performed to check the applicability of the technique to capture surface maps at high speeds. The results show that the pressure sensitivity is high enough considering the low free-stream pressure and small pressure changes expected along the flat plate surface. Initial studies have also been conducted on generating thermal bumps using a pair of electrodes. The second part deals with the experiments using laser energy deposition (volumetric localized heating) to simulate the thermal bump. The laser discharge in quiescent air with and without the plate was examined. The effect of pressure wave was investigated. The influence of the presence of an incoming hypersonic free stream is also presented. Schlieren photography and pressure measurements were employed., AFRL-AFOSR-UK-TR-2012-0020. The original document contains color images.

Cost sharing in defense acquisition, with contractors sharing part of the burden of research development, test, and evaluation (RDT&E) costs, has been suggested as a way of reducing the liability of governments to program cost overruns. While capping the costs of RDT&E and production is an excellent objective, incentivizing contractors may benefit from business models that span the entire lifecycle of a program. The potential to share the risk of cost overruns outside of RDT&E and production, and into the operations and support (O&S) area provides a powerful incentive to get contractors to buy in to cost sharing, and to control total program lifecycle costs., Excerpt from the Annual Acquisition Research Symposium (9th) held in Monterey, CA on 15-17 May 2012, Volume 1.

During the last year, we have published more than 20 research papers including 2 Science papers, 4 papers in Nature Physics and Nature Communications and 5 Phys. Rev. Letters. The most important technological result probably was the development of fabrication procedures to encapsulate graphene between boron-nitride crystals, which allows us to routinely achieve mobilities above 100,000 cm2/Vs and demonstrate room-temperature ballistic transport at micron scale (Nano Lett. 11, 2396, 2011). This development also led to the first double-layer graphene heterostructures, in which we reported interesting interaction phenomena (Nature Phys. online 2011) and which continue to be in the focus of our attention offering a wealth of new physics and potential applications. Interaction phenomena have also been studied in suspended devices made from graphene and its bilayer (Science 333, 860, 2011; Nature Phys. 7, 701, 2011) and by using the nonlocal geometry (Science 332, 328, 2011). As a result we can now routinely make and investigate complex graphene-BN heterostructures with mobilities 10 times higher than for graphene on the standard Si substrates. For suspended graphene devices, we achieve mobilities well above a million, that is, 100 times higher than for graphene on a Si substrate. Another important development over the last year was the demonstration of a graphene-based derivative, fluorographene that is a two-dimensional version of Teflon (Small 6, 2877, 2010). In all these publications, the PIs have gratefully acknowledged the AFOSR support. As concerns the entire 3-year project, it resulted in 4 Science research papers and dozens of reports in Nature series magazines, Phys. Rev. Letters, Nano Letters and other high-quality research journals. Despite the short reported period, our research has already caused very high impact that can be quantified by the number of citations for the papers supported by the AFOSR grant., The original document contains color images.

This project explored development of 'skin' material for morphing structures. Flexible fiber-reinforced composites are the prime candidates for morphing skins in order to achieve the required elongation and strength. Main objective was to develop a woven or cross ply fabric that can exhibit extension as well as shear deformations by developing and incorporating hyper-elastic yarns. These yarns consist of low modulus elastomeric core braided with high-modulus fibers. Low-modulus phase allows significant area change during deployment, and the high modulus stage provides the necessary stiffness to the skin after deployment. The 'knee-point' can be tuned to the desired strain necessary for the application by altering the manufacturing settings. In this work, two different hyper-elastic yarns were produced: biaxial braids and triaxial braids. Tensile testing showed the deformation processes to be similar. However, due to the style of interlacement, triaxial yarns achieved larger extensions. Both the styles of yarn are suitable for morphing skin applications. In addition, various braided yarns were developed by changing the pre-tension on the elastane yarn to produce different braid angles. The knee-point between low modulus and high modulus behavior was shown to shift based on braid angle, allowing a means of tuning the desired strain. A computational model for predicting the load-strain behavior of hyper-elastic yarns was developed and shown to agree well with experimental results. Finally, a woven composite was manufactured and tested as a morphing skin material using the braided yarns, and compared to analytical mechanics-based predictions., The original document contains color images.

We describe a combined dynamic atmosphere and maser propagation model of SiO maser emission in Mira variables. This model rectifies many of the defects of an earlier model of this type, particularly in relation to the infrared (IR) radiation field generated by dust and various wavelength-dependent, optically thick layers. Modelled masers form in rings with radii consistent with those found in very long baseline interferometry (VLBI) observations and with earlier models. This agreement requires the adoption of a radio photosphere of radius approximately twice that of the stellar photosphere, in agreement with observations. A radio photosphere of this size renders invisible certain maser sites with high amplification at low radii, and conceals high-velocity shocks, which are absent in radio continuum observations. The SiO masers are brightest at an optical phase of 0.1-0.25, which is consistent with observed phase lags. Dust can have both mild and profound effects on the maser emission. Maser rings, a shock and the optically thick layer in the SiO pumping band at 8.13 micrometers appear to be closely associated in three out of four phase samples., Pubb. in Monthly Note of the Royal Astronomical Society, v394, p51-66, 2009.

The MERLIN telescope, based at Jodrell Bank, achieves coherent operation using a frequency standard transmitted over microwave links. This system is locally known as the "Lband Link" (LBL). The LBL uses pulses of RF carrier waves to transmit bi-directionally between two locations in a time-division-multiplexed system (TDM). Tests in the laboratory and astronomical observations have confirmed that the LBL detects changes of delay at approximately the 1-picosecond level over periods of time extending to many hours. The legacy, radio-based, LBL terminal equipment was adapted to transmit, using thermally controlled externally modulated lasers at 1550 nanometers, over an installed fiber network of up to 110 km. The TDM operation of the LBL means that the system lasers may have very close wavelengths and are transmitted over a single fiber. Phase errors due to chromatic dispersion, circulator leakage, and differences in fiber path length are, therefore, reduced or eliminated. The round-trip delay value, halved, and the one-way path delay were measured. Any differences between the two values will indicate the error in the delay measurement, or stability, of the LBL. The objective was to establish if, in an LBL over-fiber system, an rms error close to the 1-picosecond level could be achieved. The measured rms error of the LBL over-fiber system is 1 picosecond, over sampling intervals of between 1 second and 1 minute, irrespective of fiber length. This suggests that the short-term instability seen in the results is due to terminal equipment and measurement error, rather than a fiber effect. Over a 2-hour sampling interval, an LBL over 110-km fiber system has an rms error of 4 picoseconds, compared to the legacy terminal equipment that has an rms error of 3 picoseconds, over the same period., See also ADM002186. Presented at the Annual Precise Time and Time Interval (PTTI) Systems and Appliations Meeting (40th) held in Reston, Virginia on 1-4 December 2008. Published in the Proceedings of the Annual Precise Time and Time Interval (PTTI) Systems and Appliations Meeting (40th), p107-116, 2008. The original document contains color images.

This report results from a contract tasking University of Manchester as follows: The Grantee will analytically investigate the use of a passive buckling load alleviation concept for a sensorcraft type wing configuration. The outer wing of the sensor craft design leads to the high aspect ratio, which is very favorable for reduction in fuel consumption and range extension. However, it produces high bending moments stemming from maneuvers or wind gusts. This project will investigate the use of an attachment of the outer wing that will enable passive load alleviation due to the washout deflection of the wingtip. A finite element model will be used to investigate and compare strength behavior as well as the static and dynamic aeroelastic performance. An investigation will be performed to show how the load alleviation features can be installed. A study of the outer wing will be performed to investigate the static aeroelastic behavior, position and attachment stiffness of the device. A divergence and flutter analysis will also be performed, and also a buckling analysis will be made to show that this phenomenon will not occur for limit gust or maneuver loads. An assessment of the overall weight reduction using the alleviation device will be conducted., The original document contains color images.

This report results from a contract tasking University of Manchester as follows: The investigation will be conducted in the University of Manchester hypersonic blowdown wind tunnel facility (HSST) at Mach no. 4 to 6. All experimental tasks will utilize the following experimental techniques: i) Particle Image Velocimetry (PIV) and laser sheet; ii) Intensity-based in-house developed Pressure Sensitive Paint (PSP) imaging system; iii) Pressure tapings; iv) Pitot pressure and total temperature probes; v) Oil flow; and vi) High-speed phase-locked schlieren photography and double exposure holographic interferometry. Task 1: Plasma and non-plasma (PnP) jet system and model design, and performance tests. Task 2: Transverse non-plasma jet interaction tests: Investigation of the physics of transverse non-plasma jet interactions and determination of penetration distance of the jet into the cross-flow and separation lateral spreading. Task 3: Active control of transverse jet interaction using localized arc filament plasma actuators (LAFPA): 3.1 Investigation of the physics of transverse jet interactions with LAFPA and determination of penetration distance of the jet into the cross-flow and separation lateral spreading; 3.2 Evaluation of the benefits of LAFPA system to enhance mixing of the jet with the cross flow fluid through modification of instabilities. Task 4: Transverse plasma jet interaction tests: Investigation of the physics of transverse plasma jet interactions and determination of penetration distance of the jet into the cross-flow and separation lateral spreading. Milestones: Year 1: Transverse non-plasma jet interaction studies and baseline studies on localized arc filament plasma actuator (LAFPA) system design. Year 2: Active control of transverse jet interaction using localized arc filament plasma actuators (LAFPA). Year 3: Transverse plasma jet interaction studies., The original document contains color images.

The development of several adaptive internal structures concepts is described that are aimed towards enabling adaptive static aeroelastic shape control of an aircraft wing in flight. It is shown how changes in the position, orientation and stiffness of the internal wing structure can be used to change the bending and torsion stiffness properties of a wing, and hence the control of the aerodynamic performance, in particular the lift and drag characteristics. Two approaches that implement the adaptive internal structures technology are described, based upon the rotation and chordwise translation of the spars. Following the description of conceptual studies to illustrate the concepts, the design, manufacture and testing of two wind tunnel models is described. The experimental results were found to show good agreement with static and dynamic aeroelastic behaviour predictions from Finite Element models. The feasibility of implementing the adaptive internal structures approach on full-size aircraft is discussed., See also ADM202433. Presented at the meeting on "Multifunctional Structures / Integration of Sensors and Antennas," held in Vilnius, Lithuania, on 2-4 Oct 2006. Published in the meeting proceedings, RTO-MP-AVT-141, Paper 15, p15-1 through 15-12, 2006. The original document contains color images.

A piezoelectric drop on demand printer has been used to print primary human osteoblast and bovine chondrocyte cells. After deposition the cells were incubated at 37 deg C and characterised using optical microscopy, SEM and cell viability assays. Cells showed a robust response to printing exhibiting signs of proliferation and spreading. Increasing the drop velocity results in a reduced cell survival and proliferation rates but both cell types grew to confluence after printing under all conditions studied., Presented at the Nanoscale Materials Science in Biology and Medicine held in Boston, MA on 28 Nov-2 Dec 2004. Pub. in Materials Research Society Symposium Proceedings, v845 p57-62, 2005. ISBN 1-55-899-793-8. This article is from ADA434631 Materials Research Society Symposium Proceedings. Volume 845, 2005. Nanoscale Materials Science in Biology and Medicine, Held in Boston, MA on 28 November-2 December 2004

The purpose of the study was to examine the influence of external beam radiation on the prostate and prostate cancer using novel quantitative MRI techniques. Twenty-two men, previously diagnosed with prostate cancer, were studied using T1 and T2 relaxation mapping and contrast agent kinetic methods before and after treatment by radiotherapy. The MRI findings will be correlated with biochemical (prostate specific antigen) progression and biopsy results. All 22 patients have been recruited and studied pre-treatment. So far nineteen patients have returned for follow-up MRI. The data is both complete and of a high quality. Data analysis of the pre-treatment phase has provided important and novel information about the microvascular characteristics of prostate cancer. These results have been accepted for publication in the leading radiology journal. Preliminary analysis of the post- treatment data is promising and awaits clinical interpretation., Report includes copy of author's article published in Magnetic Resonance in Medicine v47 p601-606, 2002: "Uncertainty in the Analysis of Tracer Kinetics Using Dynamic Contrast-Enhanced T1-Weighted MRI."

The production of functional tool steel components by selective laser sintering requires an understanding of the effects of the laser processing parameters on the microstructure evolution during the fabrication process. This would allow the production of tools that have predictable and reproducible microstructure good mechanical properties and low residual stresses. In this paper, finite element modelling has been carried out to investigate the temperature distribution and residual stresses during laser sintering of hot-work tool steel powders. The effects of the laser power and scanning rate on the selective laser sintering process have been investigated. Thermal residual stresses accumulated during the process have been predicted and compared with strain measurements made using neutron diffraction., This article is from the Mat. Res. Soc. Symp. Proc. Vol. 758 p47-52, 2003. This article is from ADA417756 Materials Research Society Symposium Proceedings, Volume 758 Held in Boston, Massachusetts on December 3-5, 2002. Rapid Prototyping Technologies

Tissue engineering aims to produce biological substitutes to restore or repair damaged human tissues or organs. The principle strategy behind tissue engineering involves seeding relevant cell(s) onto porous 3D biodegradable scaffolds. The scaffold acts as a temporary substrate where the cells can attach and then proliferate and differentiate. Collagen is the major protein constituent of the extracellular matrix in the human body and therefore an attractive scaffold material. Current collagen scaffolds are foams which limit the mass transport of oxygen and nutrients deep into the scaffold, and consequently cannot support the growth of thick-cross sections of tissue (greater than 500 micrometers). We have developed a novel process to make collagen and collagen-hydroxyapatite scaffolds containing an internal artificial circulatory system in the form of branching channels using a sacrificial mould, casting and critical point drying technique. The mould is made using a commercial rapid prototyping system, the Model-Maker II, and is designed to possess a series of connected shafts. The mould is dissolved away and the solvent itself removed by critical point drying with liquid carbon dioxide. Processed hydroxyapatite has been characterised by XRD and FTIR analysis. Tissue engineering with collagen scaffolds possessing controlled internal microarchitecture may be the key to growing thick cross-sections of human tissue., This article is from the Mat. Res. Soc. Symp. Proc. Vol. 758 p187-192, 2003. Prepared in cooperation with Dept. of Materials, University of Oxford, UK. This article is from ADA417756 Materials Research Society Symposium Proceedings, Volume 758 Held in Boston, Massachusetts on December 3-5, 2002. Rapid Prototyping Technologies

The direct ink-jet printing of ceramic powders requires the development of highly fluid suspensions of ceramic particles with viscosity <40 mPas. Here we describe the development of two such ceramic suspensions which contain up to 30% by volume of PZT particles in either an azeotropic mixture of MEK and ethanol or in an alkane wax at 120 deg. C. The influence of various processing parameters on fluid rheology are investigated and trial fluids have been passed through an inkjet printing head., This article is from the Mat. Res. Soc. Symp. Proc. Vol. 758 p113-118, 2003. This article is from ADA417756 Materials Research Society Symposium Proceedings, Volume 758 Held in Boston, Massachusetts on December 3-5, 2002. Rapid Prototyping Technologies

Collagen scaffolds have been produced that incorporate predefined internal channels. The scaffolds were obtained with the aid of sacrificial moulds that have been manufactured using a rapid prototyping technique. A computer aided design file of the mould was created and then realised using an ink-jet printer. A dispersion of collagen was then cast into the mould and frozen. Ethanol was used to dissolve the mould leaving the collagen which was then freeze dried to produce the final product. The scaffold was then analysed using X-ray microtomography (XMT) to determine whether the desired internal structure was obtained. It was found necessary to add saturated potassium iodide (KI) solution to the scaffold in order to analyses it satisfactorily by XMT. The resultant images indicate that the desired internal structure was obtained., This article is from the Mat. Res. Soc. Symp. Proc. Vol. 758 p181-186, 2003. Prepared in cooperation with Dept. of Materials, University of Oxford, England. This article is from ADA417756 Materials Research Society Symposium Proceedings, Volume 758 Held in Boston, Massachusetts on December 3-5, 2002. Rapid Prototyping Technologies

The current state of the art of flight flutter testing is reviewed, and areas where this part of the certification procedure could be improved are discussed. It is argued that the key towards speeding up the flight flutter test procedure, and also to reduce costs, is to reduce the number of flight test points that are required as part of the test clearance programme. To achieve this aim, the entire modelling and testing procedure needs to be improved, particularly with respect to non-linearities. Non-linear aeroelastic phenomena will then be able to be predicted more accurately. Current work in a number of relevant technologies is considered in relation to flight flutter testing. Suggestions are made as to how these aspects could be improved in order to speed up and reduce the cost of flight flutter testing, while maintaining, if not improving, the levels of safety., Presented at RTO Applied Vehicle Technology Panel (AVT) Symposium held in Paris, France on 22-25 Apr 2002. The original document contains color images. ISBN 92-837-0027-9. Text in English; p43-1/43-13. This article is from ADA415759 Reduction of Military Vehicle Acquisition Time and Cost through Advanced Modelling and Virtual Simulation (La reduction des couts et des delais d'acquisition des vehicules militaires par la modelisation avancee et la simulation de produit virtuel)

The purpose of the study is to examine the influence of external beam radiation on the prostate and prostate cancer using novel quantitative MRI techniques. Twenty-one men, previously diagnosed with prostate cancer, will be studied using T2 relaxation mapping and contrast agent kinetic methods before and after treatment by radiotherapy. The MRI findings will be correlated with biochemical (prostate specific antigen) progression and biopsy results. At the end of year 3 all 21 patients have been recruited and studied pre-treatment. Two patients have returned for follow-up MRI. The data is both complete and of a high quality. Preliminary data analysis has provided important and novel information about the microvascular characteristics of prostate cancer. These results are shortly to be presented at a leading international scientific conference and will form the basis of a manuscript currently in preparation. Furthermore, these studies have generated a parallel line of novel research; the estimation of arterial input functions using MRI., The original document contains color images. All DTIC reproductions will be in black and white.

This report results from a contract tasking University of Manchester as follows: The contractor will investigate using a variable stiffness vertical tail attachment to control aeroelastic performance over a range of dynamic pressures. The contractor will (1) Develop an adaptive stiffness attachment for vertical tail aircraft; (2) Develop an analytical model of the attachment and predict aeroelastic performance; (3) Design build and test a vertical tail model with and without a rudder to demonstrate the concept and validate the theoretical predictions; and (4) Conduct wind tunnel testing at sub and supersonic Mach Numbers; and (5) Consider the extension of the design for full-size aircraft and to quantify the benefits., The original document contains color images.

This report results from a contract tasking University of Manchester as follows: A generic all-movable vertical tail will be developed to investigate Diverging Flexible Vertical Tail Technology (DFVT). This model will be a modified version of an existing (U. of Manchester) carbon fiber composite transonic model. This model will have its boundary conditons adjusted based upon results of a previous analytical optimization study that examined weight, performance and observable benefits. A number of different parameters including: Mach number- both sub and supersonic speeds, attachment position, and variable attachment stiffnesses will also be examined experimentally in the wind tunnel at the University of Manchester, United Kingdom., The original document contains color images.

This report results from a contract tasking University of Manchester as follows: The key deliverable will be the ability to provide an improved integral condition for calculations in the main body of the flow. Given the plethora of parameters (M, Re, m, d, d/D, d/s), only a small subset of parameter space will be investigated within the available year; however a theoretical approach provides a fast means to investigate certain parameter regimes. Particular attention will be focused on the choice of (boundary) conditions to be imposed inside the cavity. Various asymptotic limits to the problem will be considered analytically, where appropriate, including the limit of very narrow and also very deep cavities. The possibility of modeling the cavity flow as incompressible will be thoroughly investigated. Also, the sensitivity of some of the underlying assumptions will be investigated. Once the micro' detail of the pressure field has been determined (through analytic and/or numerical means), a study will be undertaken to determine the best/most appropriate manner in which to construct a surface integral condition for use within the outer flow calculations. Progress of the proposed work will be monitored by means of one intermediate and one final report.

Conditions necessary for the reproducible deposition of pristine In2S3 thin films on TO-glass substrates by low temperature solution deposition have been identified. Baths containing carboxylic acids yield adherent, specular and crystalline films, within a defined pH range, dependent on the particular acid employed. Films have been characterised by XRD, SEM, XPS and electronic spectroscopy. As-deposited films were found to crystallise as tetragonal Beta-In2S3, no evidence for incorporation of hydroxy-indium species was found by XPS measurements., Pub in: Materials Research Society Symposium Proceedings, Volume 692. This article is from ADA405047 Progress in Semiconductor Materials for Optoelectronic Applications Symposium held in Boston, Massachusetts on November 26-29, 2001.

The ternary chalcopyrite semiconductor Cu(In/Ga)(Se/S)2 is currently used as an absorber layer in high efficiency thin film solar cells. In this study, various types of I-III-VI (I = Cu, III = Ga or In, VI = S or Se) thin films (CuGaS2, CuInS2 and CuInSe2) were prepared from a series of organometallic precursors, M(S/Se)2CNMeRn (M = Cu, In, Ga; R = alkyl) by aerosol-assisted chemical vapour deposition (AACVD). In contrast to the metal alkyl compounds, MR3 (M = In and Ga; R = alkyl). which are pyrophoric, the precursors are easy to synthesize by one-pot reactions and are air stable. The optimum growth temperature for the preparation of these films on glass substrates using aerosol-assisted chemical vapour deposition (AACVD) was found to be above 400 deg C in terms of crystallinity, although deposition does occur at lower temperatures. The films have been characterised using XRPD, SEM and EDS. SEM analyses show all films are microcrystalline. XRPD results show evidence of the crystalline nature of theses films. The results of this comprehensive study are presented and discussed., Pub in: Materials Research Society Symposium Proceedings, Volume 692. This article is from ADA405047 Progress in Semiconductor Materials for Optoelectronic Applications Symposium held in Boston, Massachusetts on November 26-29, 2001.

This report results from a contract tasking University of Manchester as follows: A generic all-movable vertical tail will be designed (at the conceptual design level) with conventional and with active flexible technologies. The weight, performance and observable benefits of such designs will then be determined relative to the conventional design. The work will examine a range of different parameters including: Mach number both sub and supersonic speeds, attachment position, yaw stiffness. The optimization will be carried out using either the La Grange code, which is already available at the University of Manchester, or the ASTROS code. A Finite Element model for a generic fin is available which was used in the DASA La Grange optimization code. This model was modified previously for the USAF-ASTROS optimization code. Part of the outcome of this work will be defining the best approach to use such multidisciplinary design and optimization codes to achieve an optimal aeroelastic design. This report results from a contract tasking University of Manchester as follows: A generic all-movable vertical tail will be designed (at the conceptual design level) with conventional and with active flexible technologies. The weight. performance and observable benefits of such designs will then be determined relative to the conventional design. The work will examine a range of different parameters including: Mach number - both sub and supersonic speeds. attachment position. yaw stiffness. The optimization will be carried out using either the La Grange code. which is already available at the University of Manchester. or the ASTROS code. A Finite Element model for a generic fin is available which was used in the DASA La Grange optimization code. This model was modified previously for the USAF-ASTROS optimization code. Part of the outcome of this work will be defining the best approach to use such multidisciplinary design and optimization codes to achieve an optimal aeroelastic designc

The purpose of the study is to examine the influence of external beam radiation on the prostate and prostate cancer using novel quantitative MRI techniques. Twenty-one men, previously diagnosed with prostate cancer, will be studied using T2 relaxation mapping and contrast agent kinetic methods before and after treatment by radiotherapy. The MRI findings will be correlated with biochemical (prostate specific antigen) progression and biopsy results. At the end of year 2 all steps are in place for the assessment and analysis of the clinical data. Ten patients have thus far been studied and a preliminary analysis of their data has been undertaken. The data is both complete and of a high quality. The findings described in year 1 have been published and there is considerable interest from the MR community in the results generated., Original contains color plates: All DTIC reproductions will be in black and white.

The characterisation of the behaviour of nonlinear aeroelastic systems has become a very important research topic. Nevertheless, most of the work carried out to date concerns the development of unsteady CFD solutions in the transonic region. Important though this work is, there is also a need for research which aims at understanding the behaviour of nonlinear systems, particularly the occurance of Limit Cycle Oscillations (LCOs). The purpose of this paper is to study the stability of a simple aeroservoelastic system with nonlinearities in the control system. The work considers both structural and control law nonlinearities and assesses the stability of the system response by use of bifurcation diagrams. It is shown that simple feedback systems designed to increase the stability of the linearised system also stabilise the nonlinear system, although their effects can be less pronounced. Additionally, a nonlinear control law designed to limit the control surfaces pitch response was found to increase the flutter speed considerably by forcing the system to undergo limit cycle oscillations instead of fluttering. Finally, friction was found to affect the damping of the system but not its stability, as long as the amplitude of the frictional force is low enough not to cause stoppages in the motion., Presented at the Specialists' Meeting of the RTO Applied Vehicle Technology Panel (AVT) held in Ottawa, Canada, 18-20 Oct 1999. This article is from ADA388195 Structural Aspects of Flexible Aircraft Control (les Aspects structuraux du controle actif et flexible des aeronefs)

This report results from a contract tasking School of Engineering University of Manchester as follows: The contractor will investigate improvements in excitations signals used in aircraft flutter flight test data collection. It describes the work done during the period 1 April - 30 September 1998 for the EOARD contract F61775-98-WEO12 on Improved Flight Flutter Testing Excitation Techniques. Strategies. A number of improved swept sine (Chirp') and random excitation signals are developed and demonstrated to be superior to conventional linear sweeps and minimum crest factor random signals.

The numerical simulation of unsteady separated turbulent flows around moving lifting surfaces is fueled by the industrial need to analyse and understand flow phenomena associated with the behaviour of aircrafts during manoeuvres. The complex flow phenomena and interactions that occur during super-manoeuvrable, high-alpha flight are highly non-linear in nature and include the occurrence of strong suction pressures, rapid movement of the stagnation point, transition of the boundary layer, formation of separation bubbles. production of shocks and most of all generation of an energetic vortical structure, referred to as the dynamic-stall vortex (DSV) that, temporarily leads to a significant lift increase (see Figure 1). Numerical simulation of such phenomena appears to be a challenging task. The phenomenon of dynamic stall (DS) has been selected as an initial point for the present study. The DS process has been under investigation for about three decades, and significant progress has been made towards understanding of the physical processes associated with rapidly pitching aerofoils beyond the static stall angle of attack., Colloquium held in Manchester, UK on 6-9 Jul 98.

This project was concerned with the link between transport and fracture in composite materials with emphasis on degradation of properties on aqueous exposure. The dependence of transport and fracture on volume fraction of a particulate filler was considered in terms of the percolation properties of the connected and unconnected particles. This report describes: validation of the percolation approach; mechanical properties ad effect of water absorption; electrical and gravimetric measurements; and ternary composites with glass and rubber.

An investigation into undoped and doped sol-gel glasses has been carried out for laser, optical and optoelectronic applications. Methods for the doping and characterization of sol-gel glasses have been developed. Lasers based on gel-silica glass doped with organic molecules and operating from the near UV to the near IR have been produced. The basic properties of the composite materials have been measured including dopant distribution, optical quality and photostability. Fundamental parameters and mechanisms for the doped systems of fluorescence lifetime, quantum efficiency and uniformity have been investigated. Controlled densification of the sol-gel glass to give increased refractive index has been demonstrated. This enables the writing of optical waveguides in bulk arid thin films which open up many applications in optoelectronics and the surface densification of sol-gel glass for lightweight optics. New methods of densification of photosensitised sol-gel glass to give high spatial resolution micron size waveguides is described. Applications for the types of systems resulting from this work are reviewed and areas of future development described.

Feedback has been used to control the vibration of dynamic structures for a number of years. The choice of sensor/actuator has always been the major challenge in feedback control. Piezoelectric materials with their small size and high sensitivity to very small displacement and forces offer a good and practical alternative to traditional magnetic or hydraulic sensor/actuators. The inverse piezoelectric effect is a property of piezoelectric materials which can be fully exploited when one component is used as both the sensor and the actuator. The initial aim of this study is to investigate how piezoceramics perform in a feedback control configuration. Subsequently the aim will be to apply the active damping concepts to plate and beam.

The development of a fully integrated whole field measurement device is discussed. The system relies on the use of electronic imaging technology, and an improved method of particle tracking to yield up to 500 vectors in less than 20 seconds. The technique is based on a modified form of cross-correlation, resulting in increased data reliability and a reduction in processing time. The system performance is fully quantified using real and simulated data. Finally its application to a convection flow is described. (Author), This article is from 'International Symposium on Applications of Laser Techniques to Fluid Mechanics and Workshop on Computers in Flow Measurements (6th) Held in Lisbon, Portugal on July 20-23, 1992', AD-A258 510, p3.3.1-3.3.6.

When doped with organic dye laser molecules, porous sol-gel prepared silica constitutes a solid state dye laser medium. In this study such media have been shown to exhibit laser action using: (a) a krypton fluoride, 249nm, laser pump producing nanosecond laser pulses and, (b) a coumarin 504 (507nm) pump producing microsecond laser pulses. The lasing thresholds were measured as l40kW/mm 3 and 1.8kW/mm 3 respectively, with lifetimes of 10-20 and 50-100 shots respectively., This articles is from 'Sol-Gel Optics: Proceedings SPIE-The International Society for Optical Engineering Held in San Diego, California on 11-13 July 1990. Volume 1328, AD-A249 986, p183 -193.

The results of studies into the interaction between sol-gel prepared silica and 10.6 micon wavelength laser radiation are presented. Hardening of the silica has been measured up to the value for fused silica. The lower densification and upper damage (bloating) thresholds were measured as 4.3 +/0. 2 and 6.3 +/- 0.3 J cm -2 of surf ace irradiated. A reflectivity refractometer has been developed to measure the refractive index of sol-gel surfaces and inconsistencies in the surface were detected resulting in variations in point-to-point measurements., This articles is from 'Sol-Gel Optics: Proceedings SPIE-The International Society for Optical Engineering Held in San Diego, California on 11-13 July 1990. Volume 1328, AD-A249 986, p474-481.