Application of precision engineering for nanometre focussing of hard X-rays in synchrotron beam lines

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.Many modern synchrotron beamlines are able to focus X-rays to a few microns in size. Although the technology to achieve this is well established, performing routine experiments with such beams is still time consuming and requires careful set up. Furthermore there is a need to be able to carry out experiments using hard X-ray beams with even smaller beams of between 100nm and 10nm. There are focussing optics that are able to do this but integrating these optics into a stable and a usable experimental set up are challenging. Experiments can often take some hours and any change in position of the beam on the sample will adversely affect the quality of the results. Experiments will often require scanning of the beam across the sample and so mechanisms suitable for high resolution but stable scanning are required. Performing routine experiments with nanometre sized beams requires mechanical systems to be able to position the sample, focussing optics, detectors and diagnostics with significantly higher levels of stability and motion resolution than is required from so called micro focus beam lines. This dissertation critically reviews precision engineering and associated technologies that are relevant for building nano focus beamlines, and the following key issues are explored: • Long term position stability due to thermal effects • Short term position stability due to vibration • Position motion with nanometre incremental motion • Results of some tests are presented and recommendations given. Some test results are presented and guidance on designing nano focus beamlines presented.Diamond Light Sourc

NASA Tech Briefs, January 2004

Topics covered include: Multisensor Instrument for Real-Time Biological Monitoring; Sensor for Monitoring Nanodevice-Fabrication Plasmas; Backed Bending Actuator; Compact Optoelectronic Compass; Micro Sun Sensor for Spacecraft; Passive IFF: Autonomous Nonintrusive Rapid Identification of Friendly Assets; Finned-Ladder Slow-Wave Circuit for a TWT; Directional Radio-Frequency Identification Tag Reader; Integrated Solar-Energy-Harvesting and -Storage Device; Event-Driven Random-Access-Windowing CCD Imaging System; Stroboscope Controller for Imaging Helicopter Rotors; Software for Checking State-charts; Program Predicts Broadband Noise from a Turbofan Engine; Protocol for a Delay-Tolerant Data-Communication Network; Software Implements a Space-Mission File-Transfer Protocol; Making Carbon-Nanotube Arrays Using Block Copolymers: Part 2; Modular Rake of Pitot Probes; Preloading To Accelerate Slow-Crack-Growth Testing; Miniature Blimps for Surveillance and Collection of Samples; Hybrid Automotive Engine Using Ethanol-Burning Miller Cycle; Fabricating Blazed Diffraction Gratings by X-Ray Lithography; Freeze-Tolerant Condensers; The StarLight Space Interferometer; Champagne Heat Pump; Controllable Sonar Lenses and Prisms Based on ERFs; Measuring Gravitation Using Polarization Spectroscopy; Serial-Turbo-Trellis-Coded Modulation with Rate-1 Inner Code; Enhanced Software for Scheduling Space-Shuttle Processing; Bayesian-Augmented Identification of Stars in a Narrow View; Spacecraft Orbits for Earth/Mars-Lander Radio Relay; and Self-Inflatable/Self-Rigidizable Reflectarray Antenna

Cutting Edge Nanotechnology

The main purpose of this book is to describe important issues in various types of devices ranging from conventional transistors (opening chapters of the book) to molecular electronic devices whose fabrication and operation is discussed in the last few chapters of the book. As such, this book can serve as a guide for identifications of important areas of research in micro, nano and molecular electronics. We deeply acknowledge valuable contributions that each of the authors made in writing these excellent chapters

The Boundary Element Method in Acoustics

The boundary element method (BEM) is a powerful tool in computational acoustic analysis. The Boundary Element Method in Acoustics serves as an introduction to the BEM and its application to acoustic problems and goes on to complete the development of computational models. Software implementing the methods is available

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 25)

Abstracts are provided for 102 patents and patent applications entered into the NASA scientific and technical information system during the period January 1984 through June 1984. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 23)

Abstracts are cited for 129 patents and patent applications introduced into the NASA scientific and technical information system during the period January 1983 through June 1983. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

Wave Chaos Studies and The Realization of Photonic Topological Insulators

Wave propagation in various complex media is an interesting and practical field that has a huge impact in our daily life. Two common types of wave propagation are examined in this thesis: electromagnetic wave propagation in complex wave chaotic enclosures, where I studied its statistical properties and explored time-domain pulse focusing, and unidirectional edge modes propagating in a reciprocal photonic topological insulator waveguide. Several theories, e.g. the Random Matrix Theory and the Random Coupling Model, have been developed and validated in experiments to understand the statistical properties of the electromagnetic waves inside wave chaotic enclosures. This thesis extends the subject from a single cavity to a network of coupled cavities by creating an innovative experimental setup that scales down complex structures, which would otherwise be too large and cumbersome to study, to a miniature version that retains its original electromagnetic properties. The process involves shrinking down the metal cavity in size by a factor of 20, increasing the electromagnetic wave frequency by the same factor and cooling down the cavity by a dilution refrigerator to reduce its ohmic loss. This experimental setup is validated by comparison with results from a full-scale setup with a single cavity and it is then extended for multiple coupled cavities. In the time domain, I utilized the time-reversal mirror technique to focus electromagnetic waves at an arbitrary location inside a wave chaotic enclosure by injecting a numerically calculated wave excitation signal. I used a semi-classical ray algorithm to calculate the signal that would be received at a transceiver port resulting from the injection of a short pulse at the desired target location. The time-reversed version of this signal is then injected into the transceiver port and an approximate reconstruction of the short pulse is observed at the target port. Photonic topological insulators are an interesting class of materials whose photonic band structure can have a bandgap in the bulk while supporting topologically protected unidirectional edge modes. This thesis presents a rotating magnetic dipole antenna, composed of two perpendicularly oriented coils fed with variable phase difference, that can efficiently excite the unidirectional topologically protected surface waves in the bianisotropic metawaveguide (BMW) structure recently realized by Ma, et al., despite the fact that the BMW medium does not break time-reversal invariance. In addition to achieving high directivity, the antenna can be tuned continuously to excite reflectionless edge modes to the two opposite directions with various amplitude ratios. Overall, this thesis establishes the foundation for further studies of the universal statistical properties of wave chaotic enclosures, and tested the limits of its deterministic properties defined by the cavity geometry. It also demonstrated in experiment the excitation of a unidirectional edge mode in a Bianisotropic Meta-waveguide, allowing for novel applications in the field of communications, for example phased array antennas

Swirl-stabilized lean-premixed flame combustion dynamics: An experimental investigation of flame stabilization, flame dynamics and combustion instability control strategies

Though modern low-emission combustion strategies have been successful in abating the emission of pollutants in aircraft engines and power generation gas turbines, combustion instability remains one of the foremost technical challenges in the development of next generation lean premixed combustor technology. Combustion instability is the coupling between unsteady heat release and combustor acoustic modes where one amplifies the other in a feedback loop. This is a complex phenomenon which involves unsteady chemical kinetic, fluid mechanic and acoustic processes that can lead to unstable behavior and could be detrimental in ways ranging from faster part fatigue to catastrophic system failure. Understanding and controlling the onset and propagation of combustion instability is therefore critical to the development of clean and efficient combustion systems. Imaging of combustion radicals has been a cornerstone diagnostic for the field of combustion for the past two decades which allows for visualization of flame structure and behavior. However, resolving both temporal and spatial structures from image-based experimental data can be very challenging. Thus, understanding flame dynamics remains a demanding task and the difficulties often lie in the chaotic and non-linear behavior of the system of interest. To this end, this work investigates the flame dynamics of lean premixed swirl stabilized flames in two distinct configurations using a variety of high fidelity optical and laser diagnostic techniques in conjunction with advanced data / algorithm based post-processing tools. The first part of this work is focused on establishing the effectiveness of microwave plasma discharges in improving combustor flame dynamics through minimizing heat release and pressure fluctuations. The effect of continuous, volumetric, direct coupled, non-equilibrium, atmospheric microwave plasma discharge on a swirl stabilized, lean premixed methane˗air flame was investigated using quantitative OH planar laser induced fluorescence (PLIF), spectrally resolved emission and acoustic pressure measurements. Proper Orthogonal Decomposition (POD) was used to post-process OH-PLIF images to extract information on flame dynamics that are usually lost through classical statistical approaches. Results show that direct plasma coupling accelerates combustion chemistry due to the non-thermal effects of plasma that lead to significantly improved combustor dynamics. Overall, this study demonstrates that microwave direct plasma coupling can drastically enhance dynamic flame stability of swirl stabilized flames especially at very lean operating conditions. The second part of this work is focused on the development of a stable and efficient small-scale combustor architecture with comparable power density, performance and emission characteristics to that of existing large-scale burners with reduced susceptibility to extinction and externally imposed acoustic perturbations while maintaining high combustion efficiency and low emission levels under ultra-lean operating conditions. Prototype burner arrays were additively manufactured, and the combustion characteristics of the mesoscale burner array were studied using several conventional and optical diagnostic techniques. The burner array was specifically configured to enhance overall combustion stability, particularly under lean operating conditions, by promoting flame to flame interactions between the neighboring elements. Dynamic mode decomposition (DMD) analysis based on high speed OH-PLIF images was carried out to provide a quantitative measure of flame stability. Results show a marked improvement in combustion stability for a mesoscale burner array compared to a single swirl-stabilized flame with similar power output. Overall, this study shows promise for integration of mesoscale combustor arrays as a flexible and scalable technology in next generation propulsion and power generation systems