scholarly journals John Edwin Field. 20 September 1936—21 October 2020

2021 ◽  
Author(s):  
Stephen M. Walley ◽  
William G. Proud ◽  
Timothy G. Leighton
Keyword(s):  
Doctoral Students ◽  
High Speed ◽  
Materials Science ◽  
Medical Physics ◽  
Strength Properties ◽  
Cavendish Laboratory ◽  
Wide Range ◽  
Practical Engineering ◽  
Experimental Physicist ◽  
Thermal Techniques

John Field was a brilliant experimental physicist who made major contributions to the physics and chemistry of solids. His research interests spanned a very wide range of topics, most of them involving energetic phenomena. These areas included the strength properties of solids, fracture growth, impact and erosion phenomena, shock physics, reactivity of solids, explosive initiation, lasers, acoustics and medical physics. Within the Physics and Chemistry of Solids Group in the Cavendish Laboratory, he developed the best-equipped high-speed camera facility in any university in Europe, including seven that achieved frame rates in excess of 10 6 frames per second. In addition to the cameras, extensive use was made of ultrasonics, optical and electron microscopy, mass spectroscopy and thermal techniques. He played an important national role in advising the Ministry of Defence on a wide range of topics in energetic phenomena and materials science, which led to practical engineering solutions. He was an outstanding supervisor of doctoral students, who remember him fondly.

Detector commissioning and development for PETRA-III

2010 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
David Pennicard ◽  
Heinz Graafsma ◽  
Michael Lohmann
Keyword(s):  
High Speed ◽  
Materials Science ◽  
Dynamic Range ◽  
Photon Counting ◽  
High Energy ◽  
X Rays ◽  
Silicon Detectors ◽  
Time Resolved ◽  
Wide Range ◽  
Synchrotron Light

The new synchrotron light source PETRA-III produced its first beam last year. The extremely high brilliance of PETRA-III and the large energy range of many of its beamlines make it useful for a wide range of experiments, particularly in materials science. The detectors at PETRA-III will need to meet several requirements, such as operation across a wide dynamic range, high-speed readout and good quantum efficiency even at high photon energies. PETRA-III beamlines with lower photon energies will typically be equipped with photon-counting silicon detectors for two-dimensional detection and silicon drift detectors for spectroscopy and higher-energy beamlines will use scintillators coupled to cameras or photomultiplier tubes. Longer-term developments include ‘high-Z’ semiconductors for detecting high-energy X-rays, photon-counting readout chips with smaller pixels and higher frame rates and pixellated avalanche photodiodes for time-resolved experiments.

The Flow of Gases at Sonic and Supersonic Speeds

1946 ◽  
Vol 155 (1) ◽  
pp. 401-416
Author(s):  
G. A. Hankins ◽  
W. F. Cope
Keyword(s):  
Compressible Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Engineering Practice ◽  
Wide Field ◽  
Design Development ◽  
Research Committee ◽  
Wide Range ◽  
Practical Engineering ◽  
The Subject

Problems involving the flow of gases at velocities near to or exceeding that of sound have been familiar to mechanical engineers for many years in connexion with the design of steam nozzles, and much valuable information has been accumulated from experience and from specific researches such as the classical work of Stodola (1927)‡ and of the Steam Nozzles Research Committee of the Institution (1923, etc.). The flow of steam through a converging-diverging nozzle, however, is only one instance of the flow of a gas in circumstances in which changes in density and pressure are produced or accompanied by changes in velocity. Behaviour of this kind is frequently referred to as compressible flow and arises in the design of gas turbines, in the jet propulsion of aircraft, in some high speed compressors, in diffusers, in flow through valves and measuring nozzles, in high speed aircraft and in the flight of projectiles. The subject of compressible flow is thus of great importance in a wide range of problems of practical engineering and as it has not yet reached a stage at which the essential features are treated in textbooks readily available to engineers, the present paper has been written to cover as wide a field as practicable. The authors' main experience of the subject has been in the field of external ballistics and in the design, development, and use of supersonic wind tunnels; and the illustrations are taken largely from such work. The principles are of universal application, and it is hoped that the discussion will be on general lines and range over a wide field of applications from various branches of engineering practice.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

Assessment of Commercial Off-the-Shelf Tissue Adhesives for Sealing Military-Relevant Corneal Perforation Injuries

2021 ◽  
Author(s):  
Eric J Snider ◽  
Lauren E Cornell ◽  
Brandon M Gross ◽  
David O Zamora ◽  
Emily N Boice
Keyword(s):  
Intraocular Pressure ◽  
High Speed ◽  
Anterior Segment ◽  
Ocular Tissue ◽  
Corneal Tissue ◽  
Corneal Perforation ◽  
Tissue Adhesives ◽  
Open Globe ◽  
Wide Range ◽  
Commercial Off The Shelf

ABSTRACT Introduction Open-globe ocular injuries have increased in frequency in recent combat operations due to increased use of explosive weaponry. Unfortunately, open-globe injuries have one of the worst visual outcomes for the injured warfighter, often resulting in permanent loss of vision. To improve visual recovery, injuries need to be stabilized quickly following trauma, in order to restore intraocular pressure and create a watertight seal. Here, we assess four off-the-shelf (OTS), commercially available tissue adhesives for their ability to seal military-relevant corneal perforation injuries (CPIs). Materials and Methods Adhesives were assessed using an anterior segment inflation platform and a previously developed high-speed benchtop corneal puncture model, to create injuries in porcine eyes. After injury, adhesives were applied and injury stabilization was assessed by measuring outflow rate, ocular compliance, and burst pressure, followed by histological analysis. Results Tegaderm dressings and Dermabond skin adhesive most successfully sealed injuries in preliminary testing. Across a range of injury sizes and shapes, Tegaderm performed well in smaller injury sizes, less than 2 mm in diameter, but inadequately sealed large or complex injuries. Dermabond created a watertight seal capable of maintaining ocular tissue at physiological intraocular pressure for almost all injury shapes and sizes. However, application of the adhesive was inconsistent. Histologically, after removal of the Dermabond skin adhesive, the corneal epithelium was removed and oftentimes the epithelium surface penetrated into the wound and was adhered to inner stromal tissue. Conclusions Dermabond can stabilize a wide range of CPIs; however, application is variable, which may adversely impact the corneal tissue. Without addressing these limitations, no OTS adhesive tested herein can be directly translated to CPIs. This highlights the need for development of a biomaterial product to stabilize these injuries without causing ocular damage upon removal, thus improving the poor vision prognosis for the injured warfighter.

scholarly journals Vibration of Rotating and Revolving Planet Rings with Discrete and Partially Distributed Stiffnesses

2020 ◽  
Vol 11 (1) ◽  
pp. 127
Author(s):  
Fuchun Yang ◽  
Dianrui Wang
Keyword(s):  
High Speed ◽  
Differential Operators ◽  
Natural Frequencies ◽  
Rotation Speed ◽  
Distribution Area ◽  
Vibration Modes ◽  
Governing Equations ◽  
Vibration Properties ◽  
Wide Range ◽  
Forced Responses

Vibration properties of high-speed rotating and revolving planet rings with discrete and partially distributed stiffnesses were studied. The governing equations were obtained by Hamilton’s principle based on a rotating frame on the ring. The governing equations were cast in matrix differential operators and discretized, using Galerkin’s method. The eigenvalue problem was dealt with state space matrix, and the natural frequencies and vibration modes were computed in a wide range of rotation speed. The properties of natural frequencies and vibration modes with rotation speed were studied for free planet rings and planet rings with discrete and partially distributed stiffnesses. The influences of several parameters on the vibration properties of planet rings were also investigated. Finally, the forced responses of planet rings resulted from the excitation of rotating and revolving movement were studied. The results show that the revolving movement not only affects the free vibration of planet rings but results in excitation to the rings. Partially distributed stiffness changes the vibration modes heavily compared to the free planet ring. Each vibration mode comprises several nodal diameter components instead of a single component for a free planet ring. The distribution area and the number of partially distributed stiffnesses mainly affect the high-order frequencies. The forced responses caused by revolving movement are nonlinear and vary with a quasi-period of rotating speed, and the responses in the regions supported by partially distributed stiffnesses are suppressed.

scholarly journals Towards a Glass New World: The Role of Ion-Exchange in Modern Technology

2021 ◽  
Vol 11 (10) ◽  
pp. 4610
Author(s):  
Simone Berneschi ◽  
Giancarlo C. Righini ◽  
Stefano Pelli
Keyword(s):  
Ion Exchange ◽  
Communication Networks ◽  
High Speed ◽  
High Performance ◽  
Low Cost ◽  
Modern Technology ◽  
Historical Background ◽  
Wide Range ◽  
Happy Marriage

Glasses, in their different forms and compositions, have special properties that are not found in other materials. The combination of transparency and hardness at room temperature, combined with a suitable mechanical strength and excellent chemical durability, makes this material indispensable for many applications in different technological fields (as, for instance, the optical fibres which constitute the physical carrier for high-speed communication networks as well as the transducer for a wide range of high-performance sensors). For its part, ion-exchange from molten salts is a well-established, low-cost technology capable of modifying the chemical-physical properties of glass. The synergy between ion-exchange and glass has always been a happy marriage, from its ancient historical background for the realisation of wonderful artefacts, to the discovery of novel and fascinating solutions for modern technology (e.g., integrated optics). Getting inspiration from some hot topics related to the application context of this technique, the goal of this critical review is to show how ion-exchange in glass, far from being an obsolete process, can still have an important impact in everyday life, both at a merely commercial level as well as at that of frontier research.

scholarly journals Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Strength Properties ◽  
Alumina Nanoparticles ◽  
Metal Powders ◽  
Wide Range ◽  
The Matrix ◽  
Spark Plasma ◽  
Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

scholarly journals Prototype Design and Experimental Evaluation of Autonomous Collaborative Communication System for Emerging Maritime Use Cases

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3871
Author(s):  
Jiri Pokorny ◽  
Khanh Ma ◽  
Salwa Saafi ◽  
Jakub Frolka ◽  
Jose Villa ◽  
...  
Keyword(s):  
Communication System ◽  
Autonomous Vehicles ◽  
High Speed ◽  
High Capacity ◽  
Workplace Safety ◽  
Unmanned Vehicles ◽  
Use Cases ◽  
Automated Systems ◽  
Collaborative Communication ◽  
Wide Range

Automated systems have been seamlessly integrated into several industries as part of their industrial automation processes. Employing automated systems, such as autonomous vehicles, allows industries to increase productivity, benefit from a wide range of technologies and capabilities, and improve workplace safety. So far, most of the existing systems consider utilizing one type of autonomous vehicle. In this work, we propose a collaboration of different types of unmanned vehicles in maritime offshore scenarios. Providing high capacity, extended coverage, and better quality of services, autonomous collaborative systems can enable emerging maritime use cases, such as remote monitoring and navigation assistance. Motivated by these potential benefits, we propose the deployment of an Unmanned Surface Vehicle (USV) and an Unmanned Aerial Vehicle (UAV) in an autonomous collaborative communication system. Specifically, we design high-speed, directional communication links between a terrestrial control station and the two unmanned vehicles. Using measurement and simulation results, we evaluate the performance of the designed links in different communication scenarios and we show the benefits of employing multiple autonomous vehicles in the proposed communication system.

scholarly journals Towards a methodology for the characterisation of the fabric of wet clays using X-ray scattering

2019 ◽  
Vol 92 ◽  
pp. 01005
Author(s):  
Georgios Birmpilis ◽  
Reza Ahmadi-Naghadeh ◽  
Jelke Dijkstra
Keyword(s):  
Materials Science ◽  
Measurement Techniques ◽  
Invasive Technique ◽  
Colloidal Systems ◽  
Characteristic Distance ◽  
X Ray ◽  
Hydrophobic Coating ◽  
X Ray Scattering ◽  
Wide Range ◽  
Ray Scattering

X-ray scattering is a promising non-invasive technique to study evolving nano- and micromechanics in clays. This study discusses the experimental considerations and a successful method to enable X-ray scattering to study clay samples at two extreme stages of consolidation. It is shown that the proposed sample environment comprising flat capillaries with a hydrophobic coating can be used for a wide range of voids ratios ranging from a clay suspension to consolidated clay samples, that are cut from larger specimens of reconstituted or natural clay. The initial X-ray scattering results using a laboratory instrument indicate that valuable information on, in principal evolving, clay fabric can be measured. Features such as characteristic distance between structural units and particle orientations are obtained for a slurry and a consolidated sample of kaolinite. Combined with other promising measurement techniques from Materials Science the proposed method will help advance the contemporary understanding on the behaviour of dense colloidal systems of clay, as it does not require detrimental sample preparation

scholarly journals Jet-Surface Interaction Test: Far-Field Noise Results

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Clifford A. Brown
Keyword(s):  
High Speed ◽  
Radial Distance ◽  
Jet Noise ◽  
Surface Interaction ◽  
Shielding Effect ◽  
Noise Prediction ◽  
Far Field ◽  
Wide Range ◽  
Field Noise ◽  
Surface Length

Many configurations proposed for the next generation of aircraft rely on the wing or other aircraft surfaces to shield the engine noise from the observers on the ground. However, the ability to predict the shielding effect and any new noise sources that arise from the high-speed jet flow interacting with a hard surface is currently limited. Furthermore, quality experimental data from jets with surfaces nearby suitable for developing and validating noise prediction methods are usually tied to a particular vehicle concept and, therefore, very complicated. The Jet-Surface Interaction Tests are intended to supply a high quality set of data covering a wide range of surface geometries and positions and jet flows to researchers developing aircraft noise prediction tools. The initial goal is to measure the noise of a jet near a simple planar surface while varying the surface length and location in order to: (1) validate noise prediction schemes when the surface is acting only as a jet noise shield and when the jet-surface interaction is creating additional noise, and (2) determine regions of interest for future, more detailed, tests. To meet these objectives, a flat plate was mounted on a two-axis traverse in two distinct configurations: (1) as a shield between the jet and the observer and (2) as a reflecting surface on the opposite side of the jet from the observer. The surface length was varied between 2 and 20 jet diameters downstream of the nozzle exit. Similarly, the radial distance from the jet centerline to the surface face was varied between 1 and 16 jet diameters. Far-field and phased array noise data were acquired at each combination of surface length and radial location using two nozzles operating at jet exit conditions across several flow regimes: subsonic cold, subsonic hot, underexpanded, ideally expanded, and overexpanded supersonic. The far-field noise results, discussed here, show where the jet noise is partially shielded by the surface and where jet-surface interaction noise dominates the low frequency spectrum as a surface extends downstream and approaches the jet plume.

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