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We developed a new system for image acquisition in dendrochronology called ATRICS. The new system was compared with existing measurement methods. Images derived from the ATRICS program and processed in any of the available programs for automatic tree-ring recognition are of much higher detail than those from flatbed scanners, as optical magnification has many advantages over digital magnification (especially in areas with extremely narrow tree rings). The quality of stitching was tested using visual assessment - no blurred areas were detected between adjacent images and no tree rings were missing because of the stitching procedure. A test for distortion showed no differences between the original and captured square, indicating that the captured images are distortion free. Differences between manual and automatic measurement are statistically insignificant. The processing of very long cores also poses no problems.

The International Workshop on "Measuring Techniques in Liquid Metal Flows" (MTLM Workshop) was organised in frame of the Dresden "Innovationskolleg Magnetofluiddynamik". The subject of the MTLM Workshop was limited to methods to determine physical flow quantities such as velocity, pressure, void fraction, inclusion properties, crystallisation fronts etc. The present proceedings contain abstracts and viewgraphs of the oral presentations. During the last decades numerical simulations have become an important tool in industry and research to study the structure of flows and the properties of heat and mass transfer. However, in case of liquid metal flows there exists a significant problem to validate the codes with experimental data due to the lack of available measuring techniques. Due to the material properties (opaque, hot, chemical aggressive) the measurement of flow quantities is much more delicate in liquid metals compared to ordinary water flows. The generalisation of results obtained by means of water models to real liquid metal flows has often to be considered as difficult due to the problems to meet the actual values of non-dimensional flow parameters (Re, Pr, Gr, Ha, etc.). Moreover, a strong need has to be noted to make measuring techniques available to monitor and to control flow processes in real industrial facilities.

The International Workshop on "Measuring Techniques in Liquid Metal Flows" (MTLM Workshop) was organised in frame of the Dresden "Innovationskolleg Magnetofluiddynamik". The subject of the MTLM Workshop was limited to methods to determine physical flow quantities such as velocity, pressure, void fraction, inclusion properties, crystallisation fronts etc. The present proceedings contain abstracts and viewgraphs of the oral presentations. During the last decades numerical simulations have become an important tool in industry and research to study the structure of flows and the properties of heat and mass transfer. However, in case of liquid metal flows there exists a significant problem to validate the codes with experimental data due to the lack of available measuring techniques. Due to the material properties (opaque, hot, chemical aggressive) the measurement of flow quantities is much more delicate in liquid metals compared to ordinary water flows. The generalisation of results obtained by means of water models to real liquid metal flows has often to be considered as difficult due to the problems to meet the actual values of non-dimensional flow parameters (Re, Pr, Gr, Ha, etc.). Moreover, a strong need has to be noted to make measuring techniques available to monitor and to control flow processes in real industrial facilities.

The poster presents two measuring techniques which, by their very nature, can be focused on, exclusively, microscopic dimensions, including the interior of the individual particles (crystallites) of the material under study. Correspondingly, they are referred to as “microscopic measuring techniques”. The examples presented refer, in particular, to the potentials of these techniques for investigating mass transfer in complex systems.

Diplomová práca je zameraná na riešenie aktuálneho a akutného problému výroby tvarovej hriadele “Hohlwelle” vo firme Vekastool. Tri návrhy riešenia boli sústredené na dokončovaciu operáciu diery 30 H7, z ktorých dva boli priamo odtestované vo firme. Jedna z nich bola návrh a realizácia nového vyvrtávacieho nástroja firmou Ham-Final , ktorá priniesla zníženie nákladov o dve tretiny.

Orientador: Evandro Conforti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-23T23:28:57Z (GMT). No. of bitstreams: 1 Ribeiro_AntonioMarceloOliveira_D.pdf: 6175407 bytes, checksum: 03c529ed2452256d1369e23e047687ec (MD5) Previous issue date: 2013 / Resumo: Os efeitos provocados pelo ambiente de propagação sobre o sinal transmitido, assim como as condições impostas pela mobilidade do receptor, afetam diretamente a qualidade de serviço em sistemas de comunicação sem fios. Portanto, é necessário compreender e analisar os efeitos de degradação que o canal terá sobre um dado sistema de comunicação de dados e, dessa forma, avaliar a necessidade de medidas para mitigar os eventuais efeitos prejudiciais do canal. Neste trabalho, apresenta-se uma caracterização estatística do canal de rádio móvel, a partir de medições em campo nas bandas de 1800, 2500 e 3500 MHz, através de uma técnica simples de aquisição da envoltória do sinal. Em particular, são calculadas, para a envoltória, funções de distribuição de probabilidade, taxas de cruzamentos, duração de desvanecimento e sua distribuição, funções de correlação espacial e em frequência, tempo de coerência e largura de banda de coerência. Realiza-se, igualmente, uma análise comparativa destes resultados com os seguintes modelos estatísticos: Rayleigh, Nakagami, Rice, Weibull, Hoyt (Nakagami-q) e ?-?. Além disso, é dada ênfase à estimação de parâmetros dos modelos de canal de rádio, através de dois métodos: momentos (MoM) e máxima verossimilhança (ML). Neste contexto, obtém-se expressões para a variância e o intervalo de confiança, assintóticos, de estimadores ML, baseadas na informação de Fisher que uma amostra aleatória contém a respeito do parâmetro a ser estimado. De forma geral, foi observado um bom ajuste entre as medidas em campo e correspondentes curvas teóricas, para estatísticas de primeira e segunda ordem da envoltória. As medições em campo deste trabalho mostraram que os estimadores ML agruparam mais as curvas teóricas, em torno da curva experimental, quando comparados aos estimadores MoM. Adicionalmente, a matriz de covariância dos estimadores ML para ? e ?, obtida a partir das medições em campo, mostrou que a variância do estimador de ? é, pelo menos, dez vezes maior que aquela do estimador de ?. Igualmente, valores medidos de correlação espacial apresentaram bom ajuste aos modelos teóricos, em termos de uma tendência geral de variação. Em particular, curvas de distribuição cumulativa do tempo de coerência, , para medidas em campo em 3500MHz, mostraram que é maior que 1,7 ms, para 90% do tempo, quando o receptor se move a 30 km/h. Por fim, medidas em campo da largura de banda de coerência, em 1800MHz, revelaram que um valor de ?f < 60 kHz irá garantir um nível de correlação da envoltória maior que 0,9, para 90% do tempo / Abstract: The propagation environment effects on the transmitted signal as well as the conditions imposed by the receiver mobility directly affect the quality of service (QoS) in wireless communication systems. Therefore, it is necessary to understand and analyze the degradation effects inflicted by the channel on a given data communication system, in order to evaluate the measures to mitigate these deleterious effects. In this thesis, we present a statistical characterization of the mobile radio channel based on field measurements performed over the 1800, 2500, and 3500 MHz bands, using a simple technique for acquiring the signal envelope. In particular, envelope statistics for probability distribution functions were calculated, as well as the crossing rates, duration of fading and its distribution, spatial and frequency correlation functions, coherence time, and coherence bandwidth. A comparative analysis of these results was also carried out against the following statistical models: Rayleigh, Nakagami, Rice, Weibull, Hoyt (Nakagami-q), and ?-?. Also, emphasis is given to the parameter estimation of radio channel models using two methods: moments (MoM) and maximum likelihood (ML). In this context, expressions for the asymptotic variance and confidence interval of ML estimators were obtained, based on the Fisher information a random sample contains over the parameter to be estimated. In general, there was a good fit between the field measurements and corresponding theoretical curves for envelope statistics of first and second order. Field measurements of this work have shown that ML estimators grouped more the theoretical curves around the experimental one, when compared to MoM estimators. Additionally, the covariance matrix of ML estimators for ? and ?, obtained from field measurements, showed that the variance of ? estimator is at least ten times greater than the one of ? estimator. Moreover, measured values of spatial correlation showed a good .t to the theoretical models, in terms of a general tendency of variation. Particularly, cumulative distribution curves of the coherence time , for field measurements at 3500MHz, showed that is greater than 1,7 ms for 90% of time when the receiver is moving at 30 km/h. Finally, 1800- MHz field measurements of coherence bandwidth revealed that a value of ?f < 60 kHz will ensure a level of envelope correlation greater than 0.9 for 90% of time / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica