International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / Aydin Vector Division has developed and manufactured an airborne, high shock, wideband FM/FM telemetry system for Saab Missiles AB in Sweden. This system was presented in the ITC Proceedings of 1988, Volume XXIV, pp 71-84 (Ref [1]). Three such systems were supplied. Saab Missiles AB also awarded Aydin Vector Division with an additional order for a larger number of high shock, computer based, specially designed, miniature PCM/FM airborne telemetry systems. These systems were developed, manufactured and supplied to Saab Missiles AB, and have been extensively and successfully used in the Swedish program. The PCM/FM telemetry package described in this paper was used for the system testing and the firing trials program of a mortar projectile, where the measurement requirements included micro processor interfaces, as well as a high amount of analog and bi-level data channels. The paper covers the specifications of the PCM/FM system mentioned above, the concept that was used to meet these specifications, the system’s mechanical and electrical design, the packaging technique and some of the test results.

International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The new generation of advanced tactical aircraft and missiles places unique demands on the electronic and mechanical designs for flight test instrumentation, high bit rates, operating temperature range and system interconnect wiring requirements. This paper describes a microminiature PCM distributed data acquisition system with integral signal conditioning (MMSC) which has been used in advanced aircraft and missile flight testing. The MMSC system is constructed from microminiature, stackable modules which allow the user to reconfigure the system as the requirements change. A second system is also described which uses the same circuitry in hermetic hybrid packages on plug-in circuit boards.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / This paper describes some of the signal conditioning and processing circuits that were developed to reconstruct the doppler video signal from a radar receiver under test. The reconstructed doppler video signal is then digitized and put into a telemetry frame for transmission to a ground receiving station.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / This paper describes the technology on transmitting a single super fast waveform signal in real-time and introduces the general situation of the telemetry transmitter in vehicle. The equipment is a FM system in view of RF frequency, it is a pulse system in view of RF power. This equipment can transfer not only super fast waveform signals but also slowly varying conventional telemetry signals. The design is very novel. It is a multi-usage telemetry transmitter in vehicle.

Thesis (MSc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The nonlinear LULU smoothers excel at removing impulsive noise from sequences and possess a variety of theoretical properties that make it possible to perform a so-called Discrete Pulse Transform, which is a novel multiresolution analysis technique that decomposes a sequence into resolution levels with a large amount of structure, analogous to a Discrete Wavelet Transform. We explore the use of a one-dimensional Discrete Pulse Transform as the central element in a digital image compressor. We depend crucially on the ability of space-filling scanning orders to map the two-dimensional image data to one dimension, sacrificing as little image structure as possible. Both lossless and lossy image compression are considered, leading to five new image compression schemes that give promising results when compared to state-of-the-art image compressors. / AFRIKAANSE OPSOMMING: Die nielineêre LULU gladstrykers verwyder impulsiewe geraas baie goed uit rye en besit verskeie teoretiese eienskappe wat dit moontlik maak om ’n sogenoemde Diskrete Puls Transform uit te voer; ’n nuwe multiresolusie analise tegniek wat ’n ry opbreek in ’n versameling resolusie vlakke wat ’n groot hoeveelheid struktuur bevat, soortgelyk tot ’n Diskrete Golfie Transform. Ons ondersoek of ’n eendimensionele Diskrete Puls Transform as die sentrale element in ’n digitale beeld kompressor gebruik kan word. Ons is afhanklik van ruimtevullende skandeer ordes om die tweedimensionele beelddata om te skakel na een dimensie, sonder om te veel beeld struktuur te verloor. Vyf nuwe beeld kompressie skemas word bespreek. Hierdie skemas lewer belowende resultate wanneer dit met die beste hedendaagse beeld kompressors vergelyk word.

Dissertation (PhD) -- Stellenbosch University, 2001 / ENGLISH ABSTRACT: Millisecond pulse forming networks (PFNs) as applicable to electro-thermal chemical (ETC) loads fall into the <1 MJ energy bracket. The energy requirements of these loads require specialised power sources involving staged energy conversion. For the <1MJ energy bracket, capacitive storage systems are usually employed. However, these systems exhibit low volume energy density and for volume sensitive applications; alternatives need to be considered. Inductive storage supplies form a sub-group of the static supplies that have theoretically superior volume energy density characteristics. This thesis documents the execution of a project concerned with the volumeoptimisation of an inductive storage supply. The system is composed of a three stage energy conversion chain. A prime power source (low power) charges an intermediate storage (IS) which is characterised by its medium power delivery capabilities. Energy is then transferred from the IS to the storage inductor which is characterised by its high power delivery capabilities. When sufficiently charged, the energy is then transferred to the load. Where pulse forming is required, the inductor storage must necessarily be modular. Switching elements to control the energy flow are also required. Work performed at Soreq, Israel, is used as the starting point. A topology variation of the XRAM topology presented by Soreq, original to this thesis, is presented and all its functioning modes are analysed. An existing volume model is analysed and expanded to incorporate heretofore unmodelled yet non-negligible considerations. The volume model generalises the effect of system modularity, subsystem technologies and allows for the incorporation of practical construction issues into the design process. The aim is to develop a 500 kJ, 80 kA, 20 kV system with a volume not exceeding lm3. This volume must include the IS, storage inductor and full switch volume. The optimisation algorithm and system topology developed in this thesis is validated through the construction and testing of a 1.2 kA, 2.5 kV 4 module prototype. A potential full ratings system, composed of contemporary device technologies and exhibiting a volume of just over 0.8m3, is proposed. / AFRIKAANSE OPSOMMING: Millisekonde pulsvormingsnetwerke, soos toegepas op elektrotermies-chemiese laste, val in die <1 MJ energievlak. Die energievereistes van hierdie tipe las vereis gespesialiseerde kragbronne wat die gestoorde energie in verskillende stadiums aan die las beskikbaar stel. Tans word kapasitiewe stelsels gewoonlik vir toepassings wat minder as 1 MJ energie benodig gebruik. ‘n Nadeel van hierdie stelsels is egter hulle relatiewe lae energiedigtheid. Vir toepassings waar lae volume van belang is, moet altematiewe metodes ondersoek word. Pulskragbronne wat van ‘n induktiewe energiestoor gebruik maak vorm ‘n deel van die klas van statiese kragbronne met hoe energiedigtheid. Hierdie tesis handel oor die optimering, in terme van volume, van ‘n induktiewe pulskragbron. Die stelsel bestaan uit drie stadiums, wat die energie van een vorm na ‘n ander omskakel en sodoende die vorm van die puls wat aan die las gelewer word, beheer. A lae-drywing primere kragbron laai ‘n medium-dry wing intermediere energiestoor. Energie word dan van die intermediere energiestoor na ‘n hoe-drywing stoorinduktor oorgedra. Nadat die induktor volgelaai is, word die energie aan die las oorgedra. Indien pulsvorming benodig word, kan van ‘n modulere induktor gebruik gemaak word. Vaste-toestand skakelelemente word gebruik om die energievloei te beheer. Navorsing wat by Soreq, in Israel, uitgevoer is, word as die vertrekpunt vir die studie gebruik. ‘n Verandering aan die XRAM topologie word voorgestel en die werking daarvan word in detail geanaliseer. ‘n Bestaande volume model word ondersoek en uitgebrei om ‘n aantal nie-weglaatbare verskynsels in aanmerking te neem. Die nuwe volume model maak voorsiening vir modulariteit, die effek van substelseltegnologie en ‘n aantal praktiese oorwegings wat in die ontwerp van die stelsel ‘n rol speel. Die finale doel is om ‘n 500 kJ, 80 kA, 20 kV stelsel in ‘n volume van 1 m3 in te pas. Hierdie volume van 1 m3 moet die intermediere energiestoor, die stoorinduktor, asook die skakelaars, bevat. Die optimeringsalgoritme en stelseltopologie wat ontwikkel is, word eksperimenteel deur middel van ‘n 1.2 kA, 2.5 kV, 4 module prototipe geverifieer. Laastens word aangetoon hoe ‘n finale stelsel, gebaseer op huidige skakelaartegnologie, met ‘n totale volume van 0.8 m3 moontlik in die toekoms ontwikkel kan word.

No description available.

The purpose of this research is to determine the feasibility of creating an affordable and durable neutron detector for usage in the field surveys, site inspections, and transportation hub monitoring. Currently, organic scintillating detectors are an established method of detecting neutrons but are either costly, fragile solids like stilbene, or flammable liquids like benzene. In this work, several scintillation mixtures were tested with a PuBe source, which emits both neutrons and gamma rays. The pulse shape discrimination method was utilized to separate the signal pulses created from the mixed radiation field of the PuBe source. Two candidate mixtures were selected for solidification with elastomers for their verified neutron detection capabilities. The solid detectors measured high energy neutrons and gamma rays from the PuBe source. The solidified detectors have a Figure of Merit for separating neutrons of 0.859 ±0.419 and cost $0.13 per gram, while commercially available stilbene separates neutrons from gammas with a Figure of Merit of 4.70 and costs $64.36 per gram. This research shows that it is feasible to create affordable solid organic scintillators sensitive to high energy neutrons.

L’Imagerie par Résonance Magnétique (IRM) est une belle application de la physique et constitue sans aucun doute l’une des techniques les plus performantes d’imagerie médicale. Basée sur le phénomène de la Résonance Magnétique Nucléaire (RMN) du proton contenu dans les molécules d’eau, l’IRM permet d’investiguer en coupes les tissus mous du corps, sur base de contrastes différents. La méthode est non-invasive et n’utilise pas de radiations ionisantes. En plus des données morphologiques, l’IRM permet également d’obtenir des informations fonctionnelles et physiologiques. De nos jours, plus de 10 000 unités IRM existent dans le monde et des millions d’examens sont réalisés chaque année. La technique est en constant développement et le domaine de recherches est multidisciplinaire. Il concerne aussi bien les développements méthodologiques (imagerie rapide, imagerie de diffusion, etc.) que technologiques (imagerie à haut champ, systèmes de gradients à commutation rapide, etc.), le point central des recherches étant l’amélioration de la qualité des images et la diminution du temps d’acquisition. Ceci implique l'optimisation des différentes séquences IRM (séries d'impulsions radiofréquence et de gradients de champ magnétique) tenant compte des contraintes imposées par le matériel, ainsi que le développement et l'optimisation du matériel lui-même. Cette thèse est consacrée au design avancé des séquences d’impulsions et contribue donc à l'optimisation des schémas d’acquisition en IRM. En particulier, le présent travail est focalisé sur la compréhension et l’amélioration d’un certain type de séquences rapides, employant des échos de gradients : les séquences Steady-State Free Precession (SSFP) et plus précisément les séquences dites balanced-SSFP. Dans ce genre de schéma d’acquisition, le système est excité rapidement et périodiquement, conduisant à l’établissement d’un état stationnaire de l’aimantation. La première partie de la thèse est consacrée à une analyse approfondie des propriétés du signal dans une séquence balanced-SSFP, à la fois à l’état stationnaire et à l’état transitoire. Ensuite, de nouveaux schémas d’acquisition sont développés sur base de calculs analytiques et de simulations numériques et sont ensuite testés expérimentalement. D’une part, une manipulation de l’état stationnaire est présentée en vue de supprimer le signal de la graisse sur les images (qui peut être gênant pour le diagnostic de certaines lésions ou maladies). D’autre part, l’application d’une phase de préparation en vue d’obtenir un contraste basé sur le degré de diffusion des molécules d’eau dans les tissus est analysée en détails, afin d’améliorer la qualité d’image produite par des séquences de diffusion existantes. La présente thèse constitue donc un travail de recherches théoriques et expérimentales, allant de la conception de nouveaux schémas d’acquisition à leur expérimentation sur volontaires, en passant par leur implémentation sur un imageur IRM. Ce travail a été réalisé au sein de l’Unité d’IRM – Radiologie de l’Hôpital Erasme, sous la direction de Thierry Metens, Docteur en Sciences et Physicien IRM.

A single-stage pulse tube cryocooler was designed and fabricated to provide cooling at 50 K for a high temperature superconducting (HTS) magnet, with a nominal electrical input frequency of 50 Hz and a maximum mean helium working gas pressure of 2.5 MPa. Sage software was used for the thermodynamic design of the pulse tube, with an initially predicted 30 W of cooling power at 50 K, and an input indicated power of 1800 W. Sage was found to be a useful tool for the design, and although not perfect, some correlation was established. The fabricated pulse tube was closely coupled to a metallic diaphragm pressure wave generator (PWG) with a 60 ml swept volume. The pulse tube achieved a lowest no-load temperature of 55 K and provided 46 W of cooling power at 77 K with a p-V input power of 675 W, which corresponded to 19.5% of Carnot COP. Recommendations included achieving the specified displacement from the PWG under the higher gas pressures, design and development of a more practical co-axial pulse tube and a multi-stage configuration to achieve the power at lower temperatures required by HTS.