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One of the key challenges in osteochondral tissue engineering is to define specified zones with varying material properties, cell types and biochemical factors supporting locally adjusted differentiation into the osteogenic and chondrogenic lineage, respectively. Herein, extrusion-based core–shell bioprinting is introduced as a potent tool allowing a spatially defined delivery of cell types and differentiation factors TGF-β3 and BMP-2 in separated compartments of hydrogel strands, and, therefore, a local supply of matching factors for chondrocytes and osteoblasts. Ink development was based on blends of alginate and methylcellulose, in combination with varying concentrations of the nanoclay Laponite whose high affinity binding capacity for various molecules was exploited. Release kinetics of model molecules was successfully tuned by Laponite addition. Core–shell bioprinting was proven to generate well-oriented compartments within one strand as monitored by optical coherence tomography in a non-invasive manner. Chondrocytes and osteoblasts were applied each in the shell while the respective differentiation factors (TGF-β3, BMP-2) were provided by a Laponite-supported core serving as central factor depot within the strand, allowing directed differentiation of cells in close contact to the core. Experiments with bi-zonal constructs, comprising an osteogenic and a chondrogenic zone, revealed that the local delivery of the factors from the core reduces effects of these factors on the cells in the other scaffold zone. These observations prove the general suitability of the suggested system for co-differentiation of different cell types within a zonal construct.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / In this paper design and development of a PC- Based S- Band Down Converter/ FM Telemetry Receiver are discussed. With the advent of Direct Digital Synthesis (DDS) & Phase Locked Loop (PLL) technology, availability of GaAs & Silicon MMICs, Coaxial Resonator Oscillator (CRO), SAW Oscillator, SAW Filters and Ceramic Filters, realisation of single card PC- Based Down Converter and Telemetry Receiver has become a reality. With the availability of Direct Digital Synthesis and Phase Locked Loop devices having microprocessor bus compatibility, opens up many application in Telemetry and Telecommunications. In this paper design of local oscillator based on hybrid DDS & PLL technique, Coaxial Resonator Oscillator and Front-end are discussed in detail.

[pt] Neste trabalho, o Método dos Elementos Finitos é aplicado na análise eletromagnética de estruturas coaxiais circularmente simétricas excitadas pelo modo TEM. A representação do campo magnético é feita através da associação de funções base polinomiais de diferentes ordens a grades que possuem elementos triangulares ou retangulares. Este trabalho apresenta um estudo comparativo entre as diversas possibilidades de associações função base e elemento, considerando o tempo de processamento computacional e a precisão exigida na simulação. A técnica é aplicada na análise de dispositivos de acoplamento entre diferentes guias coaxiais usualmente empregados em antenas de banda larga. Para validar os resultados do algoritmo, os resultados obtidos nas diversas etapas são comparados com aqueles obtidos via Método de Casamento de Modos. Além disto, a técnica é empregada para avaliar a possibilidade de utilização de dispositivos de inspeção de tubulação que utiliza uma onda TEM de alta freqüência. A onda TEM é excitada no interior da tubulação de forma que variações em suas paredes, nas condições de contorno dos campos, produzam alterações nas características de propagação, que serão detectadas e associadas às anomalias de suas paredes internas. Estes dispositivos de inspeção são empregados na indústria de petróleo e gás. / [en] In this work, the Method of Finite Element is applied in the electromagnetic analysis of circularly symmetrical coaxial structures excited by TEM mode. The representation of the magnetic field is made through the association of polynomial basis functions of different orders associated in the grids made of triangular or rectangular elements. This work presents a comparative study between different possibilities of association between basis functions and element, considering the computational time and the accuracy yielded by the simulation. The technique is applied in the electromagnetic analysis of coupling devices used to connect different coaxial waveguides operating at microwave frequencies. To validate the algorithm developed in this work, the MEF results are compared with those obtained by employing Method of Mode Matching (MMM). Moreover, the technique is also employed to evaluate the possibility of use of TEM wave highfrequency for inspection of metallic pipelines. The TEM wave is excited inside cylindrical metallic pipes and anomalies in the metallic walls are associated to the changes in the propagation characteristics. These inspection devices are intensively used in the industry of oil and gas.

[pt] Neste trabalho, o Método dos Elementos Finitos é aplicado na análise eletromagnética e no projeto de cornetas coaxiais, utilizadas como alimentador em diversos tipos de antenas refletoras omnidirecionais. Estes alimentadores são usualmente excitados por conectores comercias, necessitando de uma estrutura de adaptação para conectar-se a corneta. Este adaptador é composto de seções não uniformes de guias de ondas coaxiais, sendo necessária à inclusão de anéis dielétricos para garantir a rigidez mecânica da antena. O correto dimensionamento desses anéis e das descontinuidades de guias de onda coaxiais que compõe a estrutura de alimentação permite estabelecer um compromisso entre minimização das perdas, alargamento da banda passante e rigidez mecânica. Devido a não uniformidade encontrada nestes dispositivos de microondas, métodos numéricos devem ser utilizados na predição do seu comportamento eletromagnético. Neste trabalho, o algoritmo baseado em Método de Elementos Finitos é utilizado para avaliar o desempenho detalhado dos diversos elementos que compõe o adaptador. Além disto, é comparado o desempenho de diversas formas e dimensões que caracterizam a corneta eletromagnética. Para validar os resultados do algoritmo, os resultados obtidos nas diversas etapas são comparados com aqueles obtidos via Método de Casamento de Modos. / [en] In this work, the Method of Finite Element is applied in the electromagnetic analysis and project of coaxial horns employed as feed in omnidirectional reflector antennas. These feeds are usually excited by standard commercial connectors that require an adaptor to connect to the coaxial horn. This adaptor is usually composed of non-uniform sections of coaxial wave guide, where dielectric rings are used to give the mechanical strength to the structure. The adequate dimensioning of these coaxial sections leads to a compromise between the minimization of return loss, the required frequency operation band, and the necessary mechanical rigidity of the structure. Due to the non-uniformities, numerical methods are required to predict the electromagnetic behavior. In this work, an algorithm based on Method of Finite Elements is used to evaluate the performance of the sections that composed the feed chain. The performance of different types of horn sections and dimensions are explored by using the algorithm. To validate the results obtained by using Method of Finite Elements they are compared with those obtained by employing Method of Mode Matching.

Submitted by Aline Batista (alinehb.ufpel@gmail.com) on 2017-08-16T14:21:20Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) José_Henrique_Nunes_Flores_Modelagem_matemática_da_perda_de_carga_em_emissores_integrados_a_tubulação_de_irrigação_localizada.pdf: 4719317 bytes, checksum: b86c8f8b440b56d663a03abb04efaf4f (MD5) / Made available in DSpace on 2017-08-16T14:21:20Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) José_Henrique_Nunes_Flores_Modelagem_matemática_da_perda_de_carga_em_emissores_integrados_a_tubulação_de_irrigação_localizada.pdf: 4719317 bytes, checksum: b86c8f8b440b56d663a03abb04efaf4f (MD5) Previous issue date: 2017-02-20 / Sem bolsa / Os objetivos deste trabalho foram: (i) Determinar a perda de carga em função da geometria dos emissores, bem como desenvolver uma relação entre a perda de carga localizada, causada pela inserção do emissor, e as características geométricas da tubulação, mediante a utilização do índice de obstrução, para tubogotejadores com emissores integrados do tipo pastilha; e (ii) Gerar um modelo semiteórico, para estimativa da perda de carga localizada no emissor, causada por sua inserção dentro da tubulação, para tubos emissores integrados do tipo pastilha. Para isso, utilizou-se uma bancada experimental desenvolvida para controle do sistema, e obtenção das variáveis pertinentes ao estudo (vazão, temperatura e perda de carga total no tubo emissor). Obteve-se então, através da utilização da equação da continuidade, a velocidade de escoamento. A partir da diferença da perda de carga total no tubo emissor do valor obtido com o cálculo da perda de carga continua na tubulação, obteve-se a perda de carga localizada causada pela inserção do emissor. Através de um projetor ótico de perfil, foram determinadas as características geométricas dos tubos emissores (áreas de seção transversal e perímetros molhados). Obteve-se, a partir da perda de carga localizada no emissor e da carga cinética, o coeficiente k, e gerou-se um modelo para sua estimativa baseado no índice de obstrução. Desenvolveu-se um modelo semiteórico para estimativa da perda de carga no emissor, a partir do Teorema de Bélanger, levando em consideração as características geométricas da tubulação. Os emissores escolhidos para este estudo são: (a) AZUD Premier Line PC; (b) Naan Dan Jain Amnon Drip AC; e (c) Rain Bird XF-SDI. Os resultados permitiram inferir que a perda de carga total no tubo emissor e a perda de carga localizada no emissor apresentaram relação potencial com a vazão. As razões de obstrução dos emissores foram 0,62, 0,68, e 0,65, e os índices de obstrução 0,37, 0,22, e 0,28, para os emissores AZUD Premier Line PC, Naan Dan Jain Amnon Drip AC, e Rain Bird XF-SDI, respectivamente. Já os coeficientes k foram, respectivamente, 1,03, 1,07, e 0,86, para os emissores AZUD Premier Line PC, Naan Dan Jain Amnon Drip AC e Rain Bird XF-SDI. O modelo potencial correlacionando o coeficiente k com o índice de obstrução, foi k=1,66 IO0,413. Em relação ao modelo semiteórico proposto, houve superestimava em 9% e 2%, para os emissores AZUD Premier Line PC e Rain Bird XF-SDI, respectivamente, e subestimativa em 34% para o emissor Naan Dan Jain Amnon Drip AC, apresentando ajuste considerado muito bom, através do índice c, para os três emissores estudados. Conclui-se que cada emissor apresentou um valor para o coeficiente k, existindo correlação com a geometria do tubo emissor, e que o modelo semiteórico proposto, pode ser utilizado para emissores de geometria semelhantes ao AZUD Premier Line PC e Rain Bird XFSDI. / The objectives of this work was: (i) To determine the variability of the head loss as a function of the geometry of the emitters, as well as to develop a relation between the local head loss caused by the emitter insertion and the geometric characteristics of the emitting pipe, using the obstruction index, for emitting pipes with non-coaxial emitters; and (ii) Generate a semi-analytical model to estimate the local head loos in the emitter, caused by its insertion into the pipeline, for emitting pipes with non-coaxial emitters. For this, an experimental bench was developed to control the system and obtain the variables pertinent to the study (flow, temperature and total head loss in the emitter pipe). Then, through the use of the continuity equation, the flow velocity was obtained. From the difference of the total head loss in the emitter pipe and the value obtained with the calculation of the continuous head loss in the pipeline, the local head loss caused by the insertion of the emitter was obtained. The geometric characteristics of the emitting tubes (cross-sectional areas and wetted perimeters) were determined through an optical profile projector. The k coefficient was obtained from the local head loss in the emitter and kinetic energy, and a model was generated for its estimation based on the obstruction index. A semi-analytical model was developed to estimate the head loss in the emitter from the Bélanger Theorem, taking into account the geometric characteristics of the pipe. The emitters chosen for this study are: (a) AZUD Premier Line PC; (b) Naan Dan Jain Amnon Drip AC; And (c) Rain Bird XF-SDI. The results allowed to infer that the total head loss in the emitter pipe and the local head loss in the emitter presented a potential relation with the flow rate. Emitter obstruction ratio were 0.62, 0.68, and 0.65, and obstruction index was 0.37, 0.22, and 0.28 for the emitters AZUD Premier Line PC, Naan Dan Jain Amnon Drip AC, and Rain Bird XFSDI, respectively. The k coefficients were 1.03, 1.07 and 0.86, respectively, for the AZUD Premier Line PC, Naan Dan Jain Amnon Drip AC and Rain Bird XF-SDI emitters respectively. The potential model correlating the k coefficient with the obstruction index was k=1,66 OI0,413. In relation to the proposed semi-analytical model, there was a 9% and 2% overestimation of the AZUD Premier Line PC and Rain Bird XF-SDI emitters, respectively, and a 34% underestimation by Naan Dan Jain Amnon Drip AC, but presenting an adjustment considered very good, through the index c, for the three emitters studied. It is concluded that each emitter presented a value for the k coefficient, there being a correlation with the geometry of the emitter tube, and that the proposed semi-analytical model can be used for geometric emitters similar to AZUD Premier Line PC and Rain Bird XF-SDI.

This document describes the design and deployment of a first generation water vapor density sensing unit, the HumiSense. This device is based on an open, air-filled capacitor which is part of a resonant circuit. The frequency of the resonant circuit mixed with a fixed frequency oscillator is the basis of the method to generate a signal that is associated to the change in water vapor density within the open capacitor with time. The physical testing results were inconclusive given that there were many unresolved artifacts in the data. Several suggestions for improving the device for future device generations were provided. / Graduation date: 2013

We introduce an approach to implement full coherent control on nanometer length scales. It is based on spatiotemporal modulation of the surface plasmon polariton (SPP) fields at the thick edge of a nanowedge. The SPP wavepackets propagating toward the sharp edge of this nanowedge are compressed and adiabatically concentrated at a nanofocus, forming an ultrashort pulse of local fields. The profile of the focused waveform as a function of time and one spatial dimension is completely coherently controlled. We establish the principal limits for the nanoconcentration of the terahertz (THz) radiation in metal/dielectric waveguides and determine their optimum shapes required for this nanoconcentration. We predict that the adiabatic compression of THz radiation from the initial spot size of vacuum wavelength R λ 300 μm 0 0 ≈ ≈ to the unprecedented final size of R = 100 − 250 nm can be achieved, while the THz radiation intensity is increased by a factor of 10 to 250. This THz energy nanoconcentration will not only improve the spatial resolution and increase the signal/noise ratio for THz imaging and spectroscopy, but in combination with the recently developed sources of powerful THz pulses, will allow the observation of nonlinear THz effects and a variety of nonlinear spectroscopies (such as two-dimensional spectroscopy), which are highly informative. This should find a wide spectrum of applications in science, engineering, biomedical research and environmental monitoring. We also develop a theory of the spoof plasmons propagating at the interface between a dielectric and a real conductor. The deviation from a perfect conductor is introduced through a finite skin depth. The possibilities of guiding and focusing of spoof plasmons are considered. Geometrical parameters of the structure are found which provide a good guiding of such modes. Moreover, the limit on the concentration by means of planar spoof plasmons in case of non-ideal metal is established. These properties of spoof plasmons are of great interest for THz technology.

We introduce an approach to implement full coherent control on nanometer length scales. It is based on spatiotemporal modulation of the surface plasmon polariton (SPP) fields at the thick edge of a nanowedge. The SPP wavepackets propagating toward the sharp edge of this nanowedge are compressed and adiabatically concentrated at a nanofocus, forming an ultrashort pulse of local fields. The profile of the focused waveform as a function of time and one spatial dimension is completely coherently controlled. We establish the principal limits for the nanoconcentration of the terahertz (THz) radiation in metal/dielectric waveguides and determine their optimum shapes required for this nanoconcentration. We predict that the adiabatic compression of THz radiation from the initial spot size of vacuum wavelength ~300 μm to the unprecedented final size of 100-250 nm can be achieved, while the THz radiation intensity is increased by a factor of 10 to 250. This THz energy nanoconcentration will not only improve the spatial resolution and increase the signal/noise ratio for THz imaging and spectroscopy, but in combination with the recently developed sources of powerful THz pulses, will allow the observation of nonlinear THz effects and a variety of nonlinear spectroscopies (such as two-dimensional spectroscopy), which are highly informative. This should find a wide spectrum of applications in science, engineering, biomedical research and environmental monitoring. We also develop a theory of the spoof plasmons propagating at the interface between a dielectric and a real conductor. The deviation from a perfect conductor is introduced through a finite skin depth. The possibilities of guiding and focusing of spoof plasmons are considered. Geometrical parameters of the structure are found which provide a good guiding of such modes. Moreover, the limit on the concentration by means of planar spoof plasmons in case of non-ideal metal is established. These properties of spoof plasmons are of great interest for THz technology.