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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Tychonoff's theorem and its equivalence with the axiom of choice

Törnkvist, Robin January 2015 (has links)
In this essay we give an elementary introduction to topology so that we can prove Tychonoff’s theorem, and also its equivalence with the axiom of choice. / Denna uppsats tillhandahåller en grundläggande introduktion till topologi för att sedan bevisa Tychonoff’s theorem, samt dess ekvivalens med urvalsaxiomet.
92

MINIATURE TELEMETRY SYSTEM FOR THE COMPACT KINETIC ENERGY MISSILE

Haataja, M. Shannon, Ambrose, Mark 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / The Compact Kinetic Energy Missile (CKEM) is currently being developed as the Army’s newest hypervelocity anti-tank missile. The project has recently transitioned from the Science and Technology Objective phase to the Advanced Technology Demonstration phase. Science and technology phase flight testing required the development of a miniature telemetry system for measuring the super sonic flight dynamics of the airframe, as well as, monitoring of the on board flight computer. Design challenges included a small mechanical envelope, limited power budget, numerous analog measurements, computer serial stream processing, and harsh launch and flight dynamics. Two versions of the system were developed in support of the partnership effort between the Army Missile Research, Development, and Engineering Center (AMRDEC) and industry. This paper will focus on the successful design, development, and flight tests of the CKEM telemetry system.
93

Printed/additively manufactured and compact antennas for IoT and wearable applications

Nate, Kunal A. 27 May 2016 (has links)
The research provided in this thesis focuses on the development of the novel additively manufactured antennas using the additive 3-D and material inkjet printing fabrication as well as the conventional subtractive manufacturing by using milling machine for the compact Internet of Things (IoT) and wearable applications. The initial part of the work focuses on the different ways of fabrication of the additively manufactured antenna that includes Finite Deposition Method (FDM) and PolyJet 3-D printing technique for the substrate material fabrication. And the material inkjet printing for the conductive radiating antenna element fabrication. The document discusses the unconventional issue of the surface roughness in the 3-D printed substrates materials. The later part focuses on the designing and testing techniques for the compact electrically small antennas (ESA) for the compact IoT applications.
94

COMPACT HIGH-SPEED DISK RECORDER

Bougan, Timothy B. 10 1900 (has links)
International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / In order to meet the high-speed and high-density recording requirements for today's development and testing environments, we are seeking to merge the cutting edge technologies of tiny, high-performance disk drives and field programmable gate arrays (FPGAs) to build a high-speed compact disk recorder (CHSDR). Specifically, we designed, built, and tested a multi-drive controller that handles the interleaving of data to eight inexpensive IDE drives. These drives and controller comprise a "cell" capable of transferring data at 2.45 MB/sec (4 to 5 times the rate of a single drive). Furthermore, these "cells" can be run in parallel (with a single controller interleaving data between the cells). This "tree" effect multiplies the data rate by the number of cells employed. For example, 8 cells (of 8 drives each) can reach nearly 20 MB/second (sustained) and can be built for less than $30,000. The drives we used are the size of match boxes (the Hewlett Packard KittyHawk). These tiny drives hold 42 megabytes each and can withstand 150 Gs while operating. The cell controller is a Xilinx 4005 FPGA. Furthermore, we've designed a 120 MB/sec RAM FIFO to buffer data entering the system (to account for unavoidable drive seek latencies). In short, the compact high-speed disk array is a small, relatively low cost recording solution for anyone requiring high data speed but modest data volume. Missile shots, nuclear tests, and other short-term experiments are good examples of such requirements.
95

DETERMINATION OF AN OPTIMAL DATA BUS ARCHITECTURE FOR A FLIGHT DATA SYSTEM

Crawford, Kevin, Johnson, Martin 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / NASA/Marshall Space Flight Center (MSFC) is continually looking for methods to reduce cost and schedule while keeping the quality of work high. MSFC is NASA’s lead center for space transportation and microgravity research. When supporting NASA’s programs several decisions concerning the avionics system must be made. Usually many trade studies must be conducted to determine the best ways to meet the customer’s requirements. When deciding the flight data system, one of the first trade studies normally conducted is the determination of the data bus architecture. The schedule, cost, reliability, and environments are some of the factors that are reviewed in the determination of the data bus architecture. Based on the studies, the data bus architecture could result in a proprietary data bus or a commercial data bus. The cost factor usually removes the proprietary data bus from consideration. The commercial data bus architecture’s range from Versa Module Euro card (VME) to Compact PCI to STD 32 to PC 104. If cost, schedule and size are prime factors, VME is usually not considered. If the prime factors are cost, schedule, and size then Compact PCI, STD 32 and PC 104 are the choices for the data bus architecture. MSFC’s center director has funded a study from his discretionary fund to determine an optimal low cost commercial data bus architecture. The goal of the study is to functionally and environmentally test Compact PCI, STD 32 and PC 104 data bus architectures. This paper will summarize the results of the data bus architecture study.
96

Accretion disks in low-mass X-ray binaries in ultraviolet and optical wavelengths

Bayless, Amanda Jo 02 November 2010 (has links)
We present new models for two low-mass X-ray binaries (LMXB), 4U 1822-371 and V1408 Aql (= 4U 1957+115). The eclipsing LMXB 4U 1822-371 is the prototypical accretion disk corona (ADC) system. We have obtained new time-resolved UV spectroscopy of 4U 1822-371 with the Advanced Camera for Surveys/Solar Blind Channel on the Hubble Space Telescope and new V- and J- band photometry with the 1.3-m SMARTS telescope at Cerro Tololo Inter-American Observatory. We use the new data to construct the UV/optical spectral energy distribution of 4U 1822-371 and its orbital light curve in the UV, V , and J bands. We derive an improved ephemeris for the optical eclipses and confirm that the orbital period is changing rapidly, indicating extremely high rates of mass flow in the system; and we show that the accretion disk in the system has a strong wind with projected radial velocities up to 4400 km s⁻¹. We show that the disk has a vertically extended, optically thick component at optical wavelengths. This component extends almost to the edge of the disk and has a height equal to ~0.5 of the disk radius. As it has a low brightness temperature, we identify it as the optically thick base of the disk wind, not as the optical counterpart of the ADC. Like previous models of 4U 1822-371, ours needs a tall obscuring wall near the edge of the accretion disk, but we interpret the wall as a layer of cooler material at the base of the disk wind, not as a tall, luminous disk rim. V1408 Aql is a black hole candidate. We have obtained new optical photometry of this system in 2008 and 2009 with the Argos photometer on the 2.1-m Otto Struve telescope and optical spectra with the low resolution spectrometer on the Hobby Eberly telescope. From the data we derive an improved optical orbital ephemeris and a new geometric model for the system. The model uses only a simple thin disk without the need for a warped disk or a large disk rim. The orbital variation is produced by the changing aspect of the irradiated secondary star with orbital phase. The new model leaves the orbital inclination unconstrained and allows for inclinations as low as 20 degrees. The spectra is largely featureless continuum with He II and occasionally H[alpha] emission lines, and an absorption line from Na D. The lines are highly variable in strength and wavelength, but the variations do not correlate with orbital phase. / text
97

Engineered Wetlands and Reactive Bed Filters for Treatment of Landfill Leachate

Kietliñska, Agnieszka January 2004 (has links)
<p>The main objectives of this study were to investigate (i) anovel wetland treatment technology and (ii) selected bed filtermedia for the removal of contaminants from landfill leachate. Areview of the literature concerning experiences of the use ofconstructed wetlands (CW) for the removal of nitrogen fromlandfill leachate, showed that at least three groups oftreatment systems are in practice: sub-surface flow wetlands,hybrid systems (a combination of vertical and horizontal flowwetlands) and, compact constructed wetland (CCW). Most of thesetypeswere generally effective in reducing nitrogen (N,<i>e.g.</i>NH<sub>4</sub>-N, dominant N species in leachate) down toeffluent concentrations of about 10 mg L<sup>-1</sup>. Unfortunately, very little evidence ofresponsible mechanisms for the removal of N was presented,although some data indicated denitrification. The treatmentperformance of a compact constructed wetland (CCW) applied atthe Tveta Landfill, Södertälje, Sweden, wasevaluated. Chemically purified leachate and untreated leachatewere applied in periods of 7 day submergence and 7 day drainageto different sections of the CCW. The removal efficiency variedbetween 40 and 82%, and a mass removal rate of up to 5.1 g m<sup>2</sup>d<sup>-1</sup>was achieved. The chemical pre-treatment had adecisive role for the highest removal efficiencies obtained andit was unclear whether that treatment enhanced the efficiencybecause of lower toxicity and/or content of fewer competingcations. The possible combination of bed filter media and CCWas an ecotechnological treatment method for landfill leachatewas investigated by bench-scale laboratory column experiments.Reactive filter media (sorbents) was selected from their knownor suggested capacities for removal of heavy metals, nitrogenand phosphorus. Quartz sand or natural sand from an esker wasused as reference medium. Peat was used as an additionalcomponent in mixtures with the reactive media Polonite<sup>®</sup>(product from the bedrock opoka) and blastfurnace slag (BFS). A small column study also involved zeolite.Phosphorus was efficiently removed by Polonite<sup>®</sup>and NH<sub>4</sub>-N to some extent. Concerning metal removal, thebest performance was found as well for Polonite<sup>®</sup>, especially for Mn, Fe, Zn and Cu. The BFSshowed good removal efficiency for Cu, Ni and Mo. The removalof different elements was suggested to be a combination ofseveral factors,<i>e.g.</i>precipitation, ion exchange and adsorption. Priorto full-scale application of reactive filters at a landfillsite, matrix selection, filter design and operationalprocedures must be developed.</p><p><b>Keywords:</b>Blast furnace slag; Compact constructedwetland; Metals; Nitrogen; Polonite; Sorbents</p>
98

Stellar Models in General Relativity

Samuelsson, Lars January 2003 (has links)
<p>Neutron stars are some of the most fascinating objects in Nature. Essentially all aspects of physics seems to be represented inside them. Their cores are likely to contain deconfined quarks, hyperons and other exotic phases of matter in which the strong interaction is the dominant force. The inner region of their solid crust is penetrated by superfluid neutrons and their magnetic fields may reach well over 10<sup>12 </sup>Gauss. Moreover, their extreme mean densities, well above the densities of nuclei, and their rapid rotation rates makes them truly relativistic both in the special as well as in the general sense. This thesis deals with a small subset of these phenomena. In particular the exciting possibility of trapping of gravita-tional waves is examined from a theoretical point of view. It is shown that the standard condition <i>R</i> < 3<i>M</i> is not essential to the trapping mechanism. This point is illustrated using the elegant tool provided by the optical geometry. It is also shown that a realistic equation of state proposed in the literature allows stable neutron star models with closed circular null orbits, something which is closely related to trapped gravitational waves. Furthermore, the general relativistic theory of elasticity is reviewed and applied to stellar models. Both static equilibrium as well as radially oscillating configurations with elasticsources are examined. Finally, Killing tensors are considered and their applicability to modeling of stars is discussed</p>
99

The twenty-first century Colorado River hot drought and implications for the future

Udall, Bradley, Overpeck, Jonathan 03 1900 (has links)
Between 2000 and 2014, annual Colorado River flows averaged 19% below the 1906-1999 average, the worst 15-year drought on record. At least one-sixth to one-half (average at one-third) of this loss is due to unprecedented temperatures (0.9 degrees C above the 1906-1999 average), confirming model-based analysis that continued warming will likely further reduce flows. Whereas it is virtually certain that warming will continue with additional emissions of greenhouse gases to the atmosphere, there has been no observed trend toward greater precipitation in the Colorado Basin, nor are climate models in agreement that there should be a trend. Moreover, there is a significant risk of decadal and multidecadal drought in the coming century, indicating that any increase in mean precipitation will likely be offset during periods of prolonged drought. Recently published estimates of Colorado River flow sensitivity to temperature combined with a large number of recent climate model-based temperature projections indicate that continued business-as-usual warming will drive temperature-induced declines in river flow, conservatively -20% by midcentury and -35% by end-century, with support for losses exceeding -30% at midcentury and -55% at end-century. Precipitation increases may moderate these declines somewhat, but to date no such increases are evident and there is no model agreement on future precipitation changes. These results, combined with the increasing likelihood of prolonged drought in the river basin, suggest that future climate change impacts on the Colorado River flows will be much more serious than currently assumed, especially if substantial reductions in greenhouse gas emissions do not occur. Plain Language Summary Between 2000 and 2014, annual Colorado River flows averaged 19% below the 1906-1999 average, the worst 15-year drought on record. Approximately one-third of the flow loss is due to high temperatures now common in the basin, a result of human caused climate change. Previous comparable droughts were caused by a lack of precipitation, not high temperatures. As temperatures increase in the 21st century due to continued human emissions of greenhouse gasses, additional temperature-induced flow losses will occur. These losses may exceed 20% at mid-century and 35% at end-century. Additional precipitation may reduce these temperature-induced losses somewhat, but to date no precipitation increases have been noted and climate models do not agree that such increases will occur. These results suggest that future climate change impacts on the Colorado River will be greater than currently assumed. Reductions in greenhouse gas emissions will lead to lower future temperatures and hence less flow loss.
100

New generation ironing board for compact living / Nya generationens strykbräda för compact living

Lang, Johanna January 2016 (has links)
This report describes the product development thesis that was conducted as an end project in the Master programme Industrial Design at Jönköping University. The thesis has been about developing, designing and building an ironing board for compact living. The name for the product that has been developed is UNI and it is a multifunctional ironing board which can either be mounted on the wall or hanged over the door. When the ironing board is not in used, it can be folded up and will then act as a mirror. When the ironing board is folded down, parts of the mirrors frame will be folded down and act like a supporting leg for the ironing board. On the inside is shelves and hooks mounted. Here can the owner store small things like keys and jewelleries. To get the best final result, have the design process Bootcamp Bootleg been used. This design process is divided in to five different stages where different methods are used to help with moving the project forward. The CAD-programme SolidWorks 2014 was used to create the CAD-models and the renderings where made in the rendering programme Keyshot 5. The physical model which was made during this thesis, was made in a scale of 1:1. The materials that were used for the model were hard foam, metal, wood, acrylic mirror, wadding and fabric. This thesis has been performed in collaboration with the company Rörets Industrier AB located in Jönköping, Sweden. / Denna rapport beskriver examensarbete inom produktutveckling som gjordes som det slutliga projektet på Master programmet Industrial Design på Jönköpings universitet. Detta examensarbete har handlat om att utveckla, formge och bygga en strykbräda för compact living. Namnet på den produkt som blivit utvecklad är UNI och det är en multifunktionell strykbräda som kan monteras på en vägg eller hängas över en dörr. När strykbrädan inte används, kan den fällas upp och användas som en spegel. När strykbrädan är nedfälld kommer delar av spegels ram att fällas ner och fungera som ett stöttande ben. På insidan finns de hyllor och krokar monterat. Här kan ägaren förvara små föremål som nycklar eller smycken. För att få ett så bra resultat som möjligt, har design processen Bootcamp Bootleg använts. Denna process är uppdelad i fem olika steg där man använder olika metoder för att föra projektet framåt. CAD-programmet SolidWorks 2014 har använts för att skapa CAD-modellerna och renderingarna har gjorts i renderingsprogrammet Keyshot 5. Den fysiska modellen som gjorts under examensarbete, har gjorts i skala 1:1. Materialen som använts i vid bygget av modellen var hårt skum, metall, trä, spegelglas och tyg. Detta examensarbete har gjorts i samarbete med företaget Rörets Industrier AB lokaliserat i Jönköping, Sverige

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