• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 18
  • 6
  • 5
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 44
  • 9
  • 8
  • 7
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 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.
21

Meander-line multilayer magnetoimpedance: din?mica da magnetiza??o em tricamadas ferromagn?ticas / Meander-line multilayer magnetoimpedance: magnetization dinamics in ferromagnetic trilayers

Melo, Ac?cio Silveira de 23 March 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-07-03T14:11:15Z No. of bitstreams: 1 AcacioSilveiraDeMelo_DISSERT.pdf: 122869949 bytes, checksum: f9b3641fc5a1b60341859e275b85c1c3 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-07-10T12:50:20Z (GMT) No. of bitstreams: 1 AcacioSilveiraDeMelo_DISSERT.pdf: 122869949 bytes, checksum: f9b3641fc5a1b60341859e275b85c1c3 (MD5) / Made available in DSpace on 2017-07-10T12:50:20Z (GMT). No. of bitstreams: 1 AcacioSilveiraDeMelo_DISSERT.pdf: 122869949 bytes, checksum: f9b3641fc5a1b60341859e275b85c1c3 (MD5) Previous issue date: 2017-03-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O efeito magnetoimped?ncia (MI) ? uma das ferramentas mais completas para a an?-lise magn?tica de nanoestruturas, uma vez que ? poss?vel observar o comportamento mag-n?tico din?mico em diferentes faixas de frequ?ncias e campos magn?ticos aplicados, emregimes magn?ticos saturado e n?o saturados. Nos ?ltimos anos, estudos t?m investigadoa in?u?ncia da geometria das amostras no efeito MI, em particular, sistemas na forma detricamadas e de Meander-line, separadamente. Baseado nisso, este trabalho busca umaintegra??o destas duas geometrias com o objetivo de estudar as propriedades estruturais eo comportamento magn?tico quase-est?tico e din?mico em tricamadas de [NiFe/Cr/NiFe].As amostras foram produzidas atrav?s da t?cnica de Magnetron Sputtering, sobre subs-trato amorfos de vidro, com espessura das camadas ferromagn?tica variando entre 75 nm e142.5 nm, enquanto a espessura da camada de Cr varia entre 15 nm e 150 nm, totalizandoum conjunto de 10 amostras. Em particular, a espessura total da tricamada foi mantidaconstante em 300 nm independente da amostra produzida. Associado a isto, para cadaconjunto de espessura acima citado foram utilizados tr?s diferentes geometrias no planodo substrato, a primeira na forma retangular, tradicionalmente estudada, e as outrasduas na forma Meander-line, produzidas utilizando-se m?scaras durante o crescimentodos ?lmes. A caracteriza??o estrutural, atrav?s da difra??o de raios X, mostrou um com-portamento cristalogr??co tradicionalmente encontrados para ?lmes de NiFe crescidos emsubstratos amorfos, com uma textura [111]. A caracteriza??o magn?tica quase-est?tica foirealizada atrav?s de curvas de magnetiza??o, obtidas para diferentes dire??es de campomagn?tico aplicado no plano do ?lme em rela??o ao eixo principal da amostra, atrav?sda t?cnica de magnetometria de amostra vibrante (VSM). De uma forma geral, as curvasde magnetiza??o revelam propriedades magn?ticas isotr?picas no plano e s?o fortementedependentes da espessura das camadas ferromagn?ticas de NiFe. Por outro lado, umafraca depend?ncia com a geometria estudada (retangular ou Meander-line) ? observado,como esperado. Finalmente, para o estudo da din?mica da magnetiza??o, foi utilizada at?cnica de magnetoimped?ncia em uma ampla faixa de campo (?700 Oe) e frequ?ncia (0.5at? 3.0 GHz). Al?m disso, duas con?gura??es entre campos e correntes foram exploradas,denominadas aqui de con?gura??o longitudinal (campo e corrente na mesma dire??o) etransversal (campo aplicado perpendicularmente ? corrente). As medidas de magnetoim-ped?ncia apresentam uma estrutura de picos duplos ou m?ltiplos picos, caracter?sticos doefeito FMR, maior respons?vel pelas varia??es do efeito MI no intervalo de frequ?nciasestudado. Com respeito a depend?ncia do efeito em fun??o da raz?o entre as espessurasdas camadas de NiFe e Cr, ? poss?vel observar uma forte in?u?ncia da anisotropia mag-n?tica na estrutura de picos das curvas de MI, principalmente nas amostras com camadasferromagn?ticas mais espessas, este fato est? ligado a contribui??o de anisotropia parafora do plano. Por ?m, uma an?lise das curvas em rela??o a geometria das amostras re-vela mudan?as no comportamento da din?mica de magnetiza??o, acarretando em curvasassim?tricas e uma grande complexidade na estrutura de picos observado.
22

Revitalizace ramene řeky Váhu / Revitalization branch of the river Vah

Grand, Stanislav January 2018 (has links)
The diploma thesis deals with restoration of dead-end meander of the Váh river, which is facing problems with fluctuating water level, inappropriate conditions for fish population and insufficient capacity for water withdrawal to adjacent pond. The thesis consists of description of general characteristics of the area and current state of the dead-end meander, followed by the design of modifications within the meander and technical object at the inlet and hydrotechnical calculations concerning the technical object, excavation works and the time of emptying the meander.
23

Surface wave reduction in antenna arrays using metasurface inclusion for MIMO and SAR systems

Alibakhshikenari, M., Virdee, B.S., See, C.H., Abd-Alhameed, Raed, Falcone, F., Limiti, E. 19 October 2019 (has links)
Yes / An effective method is presented for suppressing mutual coupling between adjacent radiating elements which is based on metasurface isolation for MIMO and synthetic aperture radar (SAR) systems. This is achieved by choking surface current waves induced over the patch antenna by inserting a cross-shaped metasurface structure between the radiating elements. Each arm of the cross-shaped structure constituting the metasurface is etched with meander-line slot (MLS). Effectiveness of the metasurface is demonstrated for a2×2antenna array that operates over six frequency sub-bands in X, Ku and K-bands. With the proposed technique, the maximum improvement achieved in attenuating mutual coupling between neighbouring antennas is: 8.5 dB (8-8.4 GHz), 28 dB (9.6-10.8 GHz), 27 dB (11.7-12.6 GHz), 7.5 dB (13.4-14.2 GHz), 13 dB (16.5-16.8 GHz) and 22.5 dB (18.5-20.3 GHz). Furthermore, with the proposed technique (i) minimum center-to-center separation between the radiating elements can be reduced to 0.26λ0, where λ0 is 8.0 GHz; (ii) use of ground-plane or defected ground structures are unnecessary; (iii) use of short-circuited via-holes are avoided; (iv) it eliminates the issue with poor front-to-back ratio; and (v) it can be applied to existing arrays retrospectively. / H2020-MSCA-ITN-2016 SECRET-722424 and the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E0/22936/1
24

Refuge in Belen Valley

Arias-Caballero, Diego Andres 17 June 2013 (has links)
A story about love and desire to imagine architecture in a peruvian landscape. On one hand, 'Refuge in Belen Valley' is a thesis about discovering the ideal conditions that architecture should meet in a landscape, conditions that approach the idea of an offering of man rather than a conditioning for man. On the other, it is a thesis about thinking architecture as a composition derived out of material properties, emotional intentions, inhabiting possibilities and counterpoint, the arrangement of differences through dialogue. / Master of Architecture
25

Nakladatelství Meander / Meander publishing house

Havlíková, Jaroslava January 2015 (has links)
My diploma thesis called "The Meander publishing house" characterizes this publishing house in the context of the current state of the book market and children's reading. There is a paradoxical situation in the Czech Republic. Although literary production of books for children and young people increases a lot in recent years, recent readership surveys show a significant decline in reading habits. There are several institutions in the Czech Republic trying to enforce the motivation to read and to support high-quality children's publishing. The Meander publishing house is annually involved in encouraging children to read through the festival called "Děti, čtete?" (Children, do you read?). The Meander publishing house offers the quality outstanding books which resulted in increasing of the literacy level of the Czech Republic. The publishing house is connected with the name Petr Nikl, an author, artist, theater artist and musician. He is a well-rounded Czech artist and thus he is considered to be one of the most significant personalities of Czech culture. Nikl is also very popular with readership for his literary activities in the field of nonsense prose and poetry. Powered by TCPDF (www.tcpdf.org)
26

Impacts of accommodation and craft-based tourism on local economic development : the case of the Midlands Meander.

Mathfield, Damon. January 2000 (has links)
No abstract available. / Thesis (M.T.R.P.)-University of Natal, 2000.
27

Tree Community Patterns and Soil Texture Characteristics of a Meander Bend, Lower Trinity River, Southeast Texas

Nyikos, Sarah Ildiko 2011 December 1900 (has links)
Meandering rivers and associated vegetation communities are highly dynamic systems that interact through various geomorphic and successional processes. However, much is still unknown about these interactions. Studies that focus on system integration rather than examining fluvial-related and vegetation dynamics individually will benefit science and the management of river systems. Tree communities in riparian areas, although consisting mainly of bottomland hardwood species, can be very diverse. Diversity has been linked to environmental influences such as meander migration, and changes in elevation and soil texture. This study focused on a single meander bend of the lower Trinity River in southeast Texas. The purpose of this research was to examine interactions between soil texture variation and the establishment and succession of riparian tree communities, as such interactions contribute to the formation of complex riparian landscapes. A bend-scale approach was utilized to provide a detailed study of vegetation pattern and of soil texture resulting from sedimentation processes, to examine for any relationships between them. Aerial imagery was used to assist in interpreting patterns of vegetation succession. The field portion of the study collected species and size class data on trees and soil samples for textural analysis. These data were analyzed separately to understand variations in tree communities and soils, but also together, to determine any relationships between soil texture and what tree communities are able to establish. Mean annual flow data from gauges upstream and downstream of the site were analyzed for changes in flow following dam construction upstream, as river regulation could potentially alter the vegetation establishment regime. Results showed five distinct communities or zones of vegetation. Soils on the site were strongly skewed toward finer sands and high silt and clay content. Zone locations and community structure were not directly related to soil texture; however, given species had clear relationships of relative density or dominance with specific soil textures. No changes in flow were noted between pre- and post- dam construction periods, indicating that the riparian system at this site may operate under near-natural conditions. Further studies in species-soil texture interactions, and for rare and invasive species in particular, may prove beneficial in improving understanding of the complex functioning of riparian systems and in providing valuable information for their management and restoration.
28

Návrh meandrovité antény pro RFID aplikaci / Design of meander RFID antenna

Horák, David January 2008 (has links)
This thesis deals with RFID tags. In the first part of the thesis, the general overviews of the present-day RFID systems are presented. This part of the thesis is focused on the passive back-scatter UHF tags and the advantages of their application in supply chain usage. Subsequently, the electromagnetic simulators CST Microwave Studio and IE3D Zeland are described. These simulators were used to design loaded meander antennas. The antennas were designed for different materials and frequency bands of 867 MHz and 2.4 GHz. The designed antennas were made without as well as with the reflector which allows using the antennas in the vicinity of metals. Produced antennas were experimentally tested in the company METRA Blansko Inc, where one of the most significant characteristics of passive RFID tags – the read range was observed.
29

Wireless Surface Acoustic Wave Sensor for PM2.5 Detection

Mamidipally, Sai Karthik 05 1900 (has links)
Currently, there is no equipment to measure the real-time fit of EHMR or N-95masks which are used in harsh environments. Improper fit of these EHMRs or N-95 masks exposes the personnel to hazardous environments. Surface acoustic wave (SAW) sensors have been around for few decades and are being used in various applications. In this work, real-time PM2.5 detection using passive wireless SAW sensors is presented. The design of meander antenna at 433MHz for wireless interrogation of SAW sensor using HFSS and ADS is also presented in this thesis. This works also includes the design of YZ-lithium niobate SAW sensor including COMSOL simulation.
30

Design and Finite Element Modeling of a MEMS‐scale Aluminum Nitride (AlN) EnergyHarvester with Meander Spring Feature

Zula, Daniel Peter 28 August 2019 (has links)
No description available.

Page generated in 0.0559 seconds