Analysis of the influence of different initial velocities on dynamic performance of multi-layer hard target penetration process

To determine the overload characteristics of the internal system of a fuze that penetrates multilayer hard targets using different fixed-link structures, a finite element model consisting of two fixed-link structures (a compression screw and a body screw) is adopted in this paper to simulate the penetration process of a three-layer concrete target plate with corresponding initial velocities. The peak amplification coefficient and vibration coefficient are used to analyze the time-domain characteristics of the penetration process signal during segmented analysis. The extracted acceleration signals of the projectile and sensor are processed by fast Fourier transform to obtain the frequency spectrum analysis results. The simulation results show that under the same working conditions, the sensor’s ability to amplify the peak acceleration of the projectile is 17.77% higher for the body screw fixed-link structure, and the average vibration coefficient is also 9.55% higher. Compared with that of the body screw fixed-link structure, the performance of the compression screw fixed-link structure is better under different initial velocity conditions. The initial penetration velocity affects mainly the amplitude of each frequency corresponding to the acceleration signals of the two fixed-link fuze structure projectiles and sensors while having a relatively small influence on the frequency distribution position

Study of the degradation process of polyimide induced by high energetic ion irradiation

The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions and is motivated by the application of this polyimide as insulator in superconducting magnets for the new Facility for Antiproton and Ion Research (FAIR) planned at the Gesellschaft für Schwerionenforschnung (GSI). The new FAIR accelerators are expected to deliver protons and heavy ions of extreme energies (10 GeV/u) and unprecedented intensities (1E12 ions/pulse). Reliable data of the radiation hardness of polymers concerning mechanical, electrical, and outgassing properties are of great interest also for other facilities such as the Large Hadron Collider (LHC) of CERN. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1E10 – 5E12 ions/cm2). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d’ Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. Results obtained by optical spectroscopy, tensile strength measurement and mass loss analysis show similar trends and can be scaled by the irradiation dose given by the product of fluence and energy deposited along the ion trajectory. Critical material degradation appears above a dose of 1 MGy. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of non-overlapping tracks (5E10 ions/cm2). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO2, and short hydro carbons). Also a small amount of large polymer fragments is identified and confirms the degradation mechanism of Kapton proposed in earlier studies. Simultaneous in-situ infrared spectroscopy gives evidence of accumulation of these small molecules inside the bulk polymer at cryogenic temperatures. During heat-up cycles, these fragments outgas in specific temperature zones. The results obtained by the different analytical techniques allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a critical material degradation which has to be expected above a dose of 1 MGy. b) The dielectric relaxation spectroscopy indicates a dramatic increase in the conductivity induced by irradiation with heavy ions which pass a threshold of mass and deposited energy (dE/dx). The phenomenon indicates that only a few hits (fluences of 1E10 ion/cm2) of a heavy high energetic ion leads to a significant increase of conductivity. c) The degradation induced formation of small molecules and their outgassing even at cryogenic temperature cause a gas release during irradiation. At temperatures below 20 K, an additional accumulation of these molecules in the bulk material occurs and leads to a critical gas evolution during heat-up cycles

Low Frequency Electric Field Imaging

abstract: Electric field imaging allows for a low cost, compact, non-invasive, non-ionizing alternative to other methods of imaging. It has many promising industrial applications including security, safely imaging power lines at construction sites, finding sources of electromagnetic interference, geo-prospecting, and medical imaging. The work presented in this dissertation concerns low frequency electric field imaging: the physics, hardware, and various methods of achieving it. Electric fields have historically been notoriously difficult to work with due to how intrinsically noisy the data is in electric field sensors. As a first contribution, an in-depth study demonstrates just how prevalent electric field noise is. In field tests, various cables were placed underneath power lines. Despite being shielded, the 60 Hz power line signal readily penetrated several types of cables. The challenges of high noise levels were largely addressed by connecting the output of an electric field sensor to a lock-in amplifier. Using the more accurate means of collecting electric field data, D-dot sensors were arrayed in a compact grid to resolve electric field images as a second contribution. This imager has successfully captured electric field images of live concealed wires and electromagnetic interference. An active method was developed as a third contribution. In this method, distortions created by objects when placed in a known electric field are read. This expands the domain of what can be imaged because the object does not need to be a time-varying electric field source. Images of dielectrics (e.g. bodies of water) and DC wires were captured using this new method. The final contribution uses a collection of one-dimensional electric field images, i.e. projections, to reconstruct a two-dimensional image. This was achieved using algorithms based in computed tomography such as filtered backprojection. An algebraic approach was also used to enforce sparsity regularization with the L1 norm, further improving the quality of some images.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

LDEF: 69 Months in Space. Third Post-Retrieval Symposium, part 1

This volume (Part 1 of 3) is a compilation of papers presented at the Third Long Duration Exposure Facility (LDEF) Post-Retrieval Symposium. The papers represent the data analysis of the 57 experiments flown on the LDEF. The experiments include materials, coatings, thermal systems, power and propulsion, science (cosmic ray, interstellar gas, heavy ions, micrometeoroid, etc.), electronics, optics, and life science. In addition, papers on preliminary data analysis of EURECA, EOIM-3, and other spacecraft are included

The development of a warhead into an integrated weapon system to provide an advanced battlefield capability

This thesis addresses the topic of integration of weapons systems into communication networks to provide an advanced battlefield capability, with particular application to air launched and long range crew served weapon systems which may also be vehicle mounted. It considers the use of 'Military off-the-shelf' seeker, navigation and communication systems coupled with a novel tandem warhead system. This combination of 'low risk' technologies and a novel warhead system is intended to demonstrate a greater flexibility in weapon systems which could be exploited to reduce development risk, integration risk, qualification costs and increase target defeat capability across the wider more current target set. The use of a suitable communication and navigation system enabling integration of such a weapon system into a networked force was also investigated. This thesis is based on one area of research; Multiple Effects Weapons. Research is being undertaken by several nations on Multiple Effects Weapons. The aim of this research is not to provide a one weapon fits all solution, a panacea, the aim is to widen the utility of one system which could be employed in many roles. As yet no warhead system has achieved the types of effects that are being sought, although research and product development – particularly in the United States of America - continues. Therefore the United Kingdom government has sought to understand what technologies would be required to achieve a truly flexible warhead system which would enable defeat of large Main Battle Tanks, heavily armoured Infantry Fighting Vehicles, Soft Skinned Vehicles, infantry and urban structures. To this end numerical modelling, design and a demonstration programme of a MEW warhead system was performed. MEW systems are not only reliant on 'Smart' warhead systems, the application of sensors, fuzing and communication systems are crucial to enable suitable employment of a 'one size fits most' approach. The other important sub-systems which provide the link to the battlefield network are also discussed in this thesis, the inclusion of these well developed low risk technologies make it is possible to bring such systems into service in the near term with increased system flexibility. The integration of such a system relies on the current United States Department of Defense procurement strategy which includes development of the Joint Tactical Radio System radio system which will allow Ad-Hoc networking between platforms, weapons systems and commanders. Airframe and propulsion technologies are not discussed; they are outside of the scope of this thesis. The use of proprietary data from suppliers other than QinetiQ has been avoided as suitable permissions are not in place, this has limited the systems engineering aspects of this thesis to high level block diagrams which provide guidance on integration issues

Research reports: 1987 NASA/ASEE Summer Faculty Fellowship Program

For the 23rd consecutive year, a NASA/ASEE Summer Faculty Fellowship Program was conducted at the Marshall Space Flight Center (MSFC). The program was conducted by the University of Alabama in Huntsville and MSFC during the period 1 June to 7 August 1987. Operated under the auspices of the American Society for Engineering Education, the MSFC program, as well as those at other NASA Centers, was sponsored by the Office of University Affairs, NASA Headquarters, Washington, D.C. The basic objectives of the program are: (1) to further the professional knowledge of qualified engineering and science faculty members; (2) to stimulate an exchange of ideas between participants and NASA; (3) to enrich and refresh the research and teaching activities of the participant's institutions; and (4) to contribute to the research objectives of the NASA Centers. This document is a compilation of Fellow's reports on their research during the Summer of 1987

Datenakquisitionsentwicklung und Untergrundstudien für den Weltraumdetektor AMS-02 und den CMOS-Detektor MIMOSA-V

This thesis deals with the development of space qualified electronics, detector simulations and realtime data acquisition software. The covered detector designs reach from the AMS-02 experiment, as a large scale multi purpose detector with several sub-detectors for cosmic particle research, to the small single type CMOS-detector MIMOSA-V for autoradiography of micro-arrays within the REGINS project. The presented background study focuses on problems with the simulation of diffractive scattering

DRONE DELIVERY OF CBNRECy – DEW WEAPONS Emerging Threats of Mini-Weapons of Mass Destruction and Disruption (WMDD)

Drone Delivery of CBNRECy – DEW Weapons: Emerging Threats of Mini-Weapons of Mass Destruction and Disruption (WMDD) is our sixth textbook in a series covering the world of UASs and UUVs. Our textbook takes on a whole new purview for UAS / CUAS/ UUV (drones) – how they can be used to deploy Weapons of Mass Destruction and Deception against CBRNE and civilian targets of opportunity. We are concerned with the future use of these inexpensive devices and their availability to maleficent actors. Our work suggests that UASs in air and underwater UUVs will be the future of military and civilian terrorist operations. UAS / UUVs can deliver a huge punch for a low investment and minimize human casualties.https://newprairiepress.org/ebooks/1046/thumbnail.jp

NASA Tech Briefs Index, 1978

Approximately 601 announcements of new technology derived from the research and development activities of the National Aeronautics and Space Administration are presented. Emphasis is placed on information considered likely to be transferrable across industrial, regional, or disciplinary lines. Subject matter covered includes: electronic components and circuits; electron systems; physical sciences; materials; life sciences; mechanics; machinery; fabrication technology; and mathematics and information sciences