• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 789
  • 358
  • 98
  • 48
  • 46
  • 22
  • 13
  • 13
  • 8
  • 7
  • 6
  • 5
  • 5
  • 5
  • 5
  • Tagged with
  • 1664
  • 1664
  • 527
  • 315
  • 268
  • 257
  • 233
  • 191
  • 169
  • 155
  • 132
  • 125
  • 120
  • 111
  • 105
  • 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.
491

Structural studies of SpoIIAA using NMR

Comfort, David Michael January 1998 (has links)
No description available.
492

Supraspinatus Musculotendinous Architecture: A Cadaveric and In Vivo Ultrasound Investigation of the Normal and Pathological Muscle

Kim, Soo Young 24 September 2009 (has links)
The purpose of the study was to investigate the static and dynamic architecture of supraspinatus throughout its volume in the normal and pathological state. The architecture was first investigated in cadaveric specimens free of any tendon pathology. Using a serial dissection and digitization method tailored for supraspinatus, the musculotendinous architecture was modeled in situ. The 3D model reconstructed in Autodesk MayaTM allowed for visualization and quantification of the fiber bundle architecture i.e. fiber bundle length (FBL), pennation angle (PA), muscle volume (MV) and tendon dimensions. Based on attachment sites and architectural parameters, the supraspinatus was found to have two architecturally distinct regions, anterior and posterior, each with three subdivisions. The findings from the cadaveric investigation served as a map and platform for the development of an ultrasound (US) protocol that allowed for the dynamic fiber bundle architecture to be quantified in vivo in normal subjects and subjects with a full-thickness supraspinatus tendon tear. The architecture was studied in the relaxed state and in three contracted states (60º abduction with either neutral rotation, 80º external rotation, or 80º internal rotation). The dynamic changes in the architecture within the distinct regions of the muscle were not uniform and varied as a function of joint position. Mean FBL in the anterior region shortened significantly with contraction (p<0.05) but not in the posterior. In the anterior region, mean PA was significantly smaller in the middle part compared to the deep (p<0.05). Comparison of the normal and pathological muscle found large differences in the percentage change of FBL and PA with contraction. The architectural parameter that showed the largest changes with tendon pathology was PA. In sum, the results showed that the static and dynamic fiber bundle architecture of supraspinatus is heterogeneous throughout the muscle volume and may influence tendon stresses. The architectural data collected in this study and the 3D muscle model can be used to develop future contractile models. The US protocol may serve as an assessment tool to predict the functional outcome of rehabilitative exercises and surgery.
493

Erdviniai prekių ženklai ir dizainas: tarpusavio santykio problema / A Problem of Correlation Between Three-Dimensional Trademark and Design

Borneika, Nikas 24 January 2011 (has links)
Darbe analizuojamas erdvinio prekių ženklo ir dizaino tarpusavio santykis. Ši analizė paremta dviejų skirtingų pramoninės nuosavybės objektų apsaugos sistemų palyginimu. Tema yra aktuali tuo, jog prekių ženklo apsauga, kaip ir dizaino apsauga, yra galima prekės išoriniam vaizdui, t.y. erdvinei formai. Dėl šios priežasties, gamintojui, norinčiam teisinėmis priemonėmis apsaugoti savo produkto formą, atsiranda kelios galimybės. Tinkamai pasirinkti apsaugos kelią yra svarbu dėl to, jog nuo šio pasirinkimo gali priklausyti objekto apsaugos apimtis. Iš kitos pusės teorijoje pripažįstama, jog dizaino ir prekių ženklo apsaugos objektai vis dėlto privalo būti atriboti, kadangi abi apsaugos sistemos paremtos skirtingais tikslais, kurie iš esmės siejasi su pagrindiniais intelektinės nuosavybės teisės principais – užtikrinti skirtingų interesų pusiausvyrą. Teigiama, jog, neesant aiškios takoskyros, ši pusiausvyra gali būti greitai pažeista. Siekdamas išsiaiškinti šias problemas autorius gilinasi į prekių ženklo bei dizaino apsaugos teisinio reguliavimo ypatumus, t.y. reikalavimus objektams, suteikiamas teises, teisių pažeidimo nustatymo kriterijus, apsaugos terminą bei tam tikras teisės aktuose nustatytas išimtis. Išanalizavus teisinį reguliavimą, išaiškėja pagrindiniai dizaino ir prekių ženklo apsaugos privalumai ir trūkumai, bei erdvinio prekių ženklo ir dizaino atribojimo klausimai. / This paper concentrates on analysis of a correlation between three-dimensional trademark and design. Such an analysis is based on a comparison between separate systems of industrial property protection. The relevance of a subject is that trademark protection, as well as design, can be achieved on the same object – three-dimensional shape of an article. For that reason, proprietor has a several possibilities when he seeks a legal protection for a shape of product. It is important for proprietor to make a reasonable decision because the scope of protection may depend on which way of protection will be chosen. However, it is recognized that the trademark and design objects of protection has to be delimitated. It is argued that such an overlap between three-dimensional trademark and design jeopardizes the basic principles of an intellectual property law which is a balance of different public interests. In order to clarify these problems author analyzes the legal framework of trademark and design, i.e. requirements for objects, rights given by registration, test of infringement, term of protection and certain exclusions from registration. Such a review of a legal regulation will reveal the basic advantages and disadvantages of these different registration systems and help to resolve the issues of delimitation of three-dimensional trademarks and design.
494

BASIN-SCALE WAVES DYNAMICS AND SEDIMENT RESUSPENSION MECHANICS IN CENTRAL LAKE ERIE

Valipour, REZA 20 December 2012 (has links)
High-resolution physical and biogeochemical field data in central Lake Erie during the summers of 2008-2009 along with a three-dimensional numerical model were used to investigate the dynamics of basin scale waves and sediment resuspension mechanisms. In Chapter 2, the modal response of the Poincaré waves in the lake is assessed. The vertical mode-one Poincaré wave was found to be mostly dominant during the seasonal stratified period. The horizontal modal structure was also investigated in a sensitivity analysis, using the numerical model forced with real and idealized wind events. In Chapter 3, dynamics of bottom mixed layer (BML), primarily forced in the outer layer by surface seiches and Poincaré waves is studied for two 10-days representative intervals of weak and strong stratification. Shear velocity was calculated by least square fitting the well-known law-of-the-wall equation to observed near-bed velocity in a region of constant shear stress. Height of the BML is computed using water density (from water temperature) and compared with heights of logarithmic layer approximated using the law-of-the-wall equation and its modified form with buoyancy length scale term. Published equations for estimating BML heights are evaluated and modified for the lake. In Chapter 4, we investigate physical processes leading to sediment resuspension in the lake including surface waves (periods of 4-8s), up/downwelling events (periods of 3-4 day), and high frequency internal waves (periods of 5-45min). Temporal changes in near-bottom sediment resuspension are illustrated using changes in acoustic backscatter signals from current profilers and time series of turbidity measurements to identify the mechanism responsible for sediment resuspension. Resuspension is parameterized as a function of the critical velocity ~0.25ms-1 and from surface waves using linear wave theory. Finally, based on the critical velocity and sediment grain size analysis (from in-site field data), critical shear stress and Shields parameter are calculated and compared with previous observations in Lake Erie and in other locations suggesting a modified Shields diagram for silty bed materials. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2012-12-19 20:54:15.832
495

THREE-DIMENSIONAL MODELLING OF LAKE ONTARIO HYDRODYNAMICS NEAR PORT HOPE AND IN THE UPPER ST LAWRENCE RIVER

Paturi, SHASTRI 18 July 2013 (has links)
The Ontario Clean Water Act (2006) mandated that eight and two municipal drinking water intakes in the Cataraqui Region Conservation Authority (CRCA) and the Ganaraska River Source Protection Agency (GRSPA) jurisdictions respectively, be protected from contaminants released into the surrounding waters through the delineation of Intake Protection Zones (IPZs). Toward these objectives, the Estuary and Lake Computer Model (ELCOM) was applied to simulate the hydrodynamics and contaminant transport in the eastern Lake Ontario and upper St. Lawrence River. Model hydrodynamics were comprehensively validated against field data collected during April-October, 2006. The flow was found to be predominantly wind induced in the southwestern lacustrine portion of the domain and hydraulically driven in the northeastern riverine portion with storm events resulting in river flow reversals. The modeled surface currents were applied to delineate IPZs surrounding the drinking water intakes. Passive tracers were simulated as surrogates for combined sewer outflows, tributary flows, municipal/wastewater and industrial discharges identified by CRCA as threats to drinking water intakes. Wind was found to be the most dominant forcing to transport contaminants, both in the Kingston Basin and the St. Lawrence River, whereas the St. Lawrence River outflow was found to influence the transport of contaminants along the river. The hydrodynamics and contaminant transport in the near-shore region of Lake Ontario, from Port Hope to Cobourg was also simulated using ELCOM and the results were comprehensively validated against field data collected during April-September, 2010. Upwelling and downwelling events caused by south-westerly and north-easterly winds were found to be the predominant hydrodynamic process. These events generated barotropic geostrophic alongshore currents or ‘coastal jets’ of ~20 cm s-1. Discharges from river plumes and sewage treatment plants were simulated as tracer releases. The tracer concentrations were primarily influenced by the close proximity of the intakes to the effluent release points, the volume and direction of the discharge from the intakes and the physical processes driving the flow dynamics. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2013-07-17 11:41:54.68
496

Textiles in three dimensions : an investigation into processes employing laser technology to form design-led three-dimensional textiles

Matthews, Janette January 2011 (has links)
This research details an investigation into processes employing laser technology to create design-led three-dimensional textiles. An analysis of historical and contemporary methods for making three-dimensional textiles categorises these as processes that construct a three-dimensional textile, processes that apply or remove material from an existing textile to generate three-dimensionality or processes that form an existing textile into a three-dimensional shape. Techniques used in these processes are a combination of joining, cutting, forming or embellishment. Laser processing is embedded in textile manufacturing for cutting and marking. This research develops three novel processes: laser-assisted template pleating which offers full design freedom and may be applied to both textile and non-textile materials. The language of origami is used to describe designs and inspire new design. laser pre-processing of cashmere cloth which facilitates surface patterning through laser interventions in the manufacturing cycle. laser sintering on textile substrates which applies additive manufacturing techniques to textiles for the generation of three-dimensional surface patterning and structures. A method is developed for determining optimum parameters for laser processing materials. It may be used by designers for parameter selection for processing new materials or parameter modification when working across systems.
497

Visualization of Surfaces and 3D Vector Fields

Li, Wentong 08 1900 (has links)
Visualization of trivariate functions and vector fields with three components in scientific computation is still a hard problem in compute graphic area. People build their own visualization packages for their special purposes. And there exist some general-purpose packages (MatLab, Vis5D), but they all require extensive user experience on setting all the parameters in order to generate images. We present a simple package to produce simplified but productive images of 3-D vector fields. We used this method to render the magnetic field and current as solutions of the Ginzburg-Landau equations on a 3-D domain.
498

Focusing ISAR images using fast adaptive time-frequency and 3D motion detection on simulated and experimental radar data / Focusing inverse synthetic aperture radar images using fast adaptive time-frequency and three-dimensional motion detection on simulated and experimental radar data

Brinkman, Wade H. 06 1900 (has links)
Optimization algorithms were developed for use with the Adaptive Joint Time-Frequency (AJFT) algorithm to reduce Inverse Synthetic Aperture Radar (ISAR) image blurring caused by higher-order target motion. A specific optimization was then applied to 3D motion detection. Evolutionary search methods based on the Genetic Algorithm (GA) and the Particle Swarm Optimization (PSO) algorithm were designed to rapidly traverse the solution space in order to find the parameters that would bring the ISAR image into focus in the cross-range. 3D motion detection was achieved by using the AJTF PSO to extract the phases of 3 different point scatterers in the target data and measuring their linearity when compared to an ideal phase for the imaging interval under investigation. The algorithms were tested against both simulated and real ISAR data sets.
499

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting

Mun, Jiwon 12 1900 (has links)
There is a wide range of applications for 3D printing technology with an additive manufacturing such as aerospace, automotive, marine and oil/gas, medical, consumer, electronics, building construction, and many others. There have been many pros and cons for 3D additive manufacturing. Even though 3D printing technology has many advantages: freedom to design and innovate without penalties, rapid iteration through design permutations, excellence mass customization, elimination of tolling, green manufacturing, minimal material wastes, energy efficiency, an enablement of personalized manufacturing. 3D additive manufacturing still has many disadvantages: unexpected pre- and post-processing requirement, high-end manufacturing, low speed for mass production, high thermal residual stress, and poor surface finish and dimensional accuracy, and many others. Especially, the issues for 3D additive manufacturing are on high cost for process and equipment for high-end manufacturing, low speed for mass production, high thermal residual stress, and poor surface finish and dimensional accuracy. In particular, it is relatively challenging to produce casting products with lattice or honeycomb shapes having sophisticated geometries. In spite of the scalable potential of periodic cellular metals to structural applications, the manufacturing methods of I∙AM Casting have been not actively explored nor fully understood. A few qualitative studies of I∙AM Casting has been reported. Recently, a sand casting of cellular structures was attempted, resulting in casting porosity and the sharp corners in the lattice structure of the cellular structural molds, a sharpness which prevent fluid-flow and causes undesired solidification, resulting in misrun casting defects. Research on the indirect AM methods has not been aggressively conducted due to the highly complex and multidisciplinary problems across the process – continuum modeling (thermal stress, flow, heat transfer, and water diffusion) with multiple materials (polymer, metals, and ceramic) for multiphase simulations – solid, liquid, and gas. As an initial step to fully understand the processing of I∙AM Casting, a quantitative study on I∙AM Casting is conducted in this work.
500

Constructing Reality : a textile illusion!

Helgesson, Anna January 2016 (has links)
This bachelor degree work explores textile print with illusionary qualities, and aims to challenge the viewers visual perception and ideas of reality. With focus on creating three-dimensional illusionary prints the motive is to question how we evaluate design in relation to society and expected imagery. By working with the techniques of weaving, digitally developed print and transfer printing techniques this work strives to create an opportunity for the viewer to expand their idea of reality.

Page generated in 0.0967 seconds