The aim of this thesis is to design a conveyor belt readjustable to transport brown coal according to specific parameters. The introduction is focused on describing and dividing conveyor belts and characterizing their individual parts. The main part of the thesis is a description of selected components and design solutions, a functional computation carried out in accordance with the standard ČSN ISO 5048 and further an analysis of transported material's properties. The drafting documentation is attached to the thesis.

Thesis describes the design of the blocks of fractional-order filters approximation using a filter of higher order integer. Active filters of third-order are use to create filter of 1+alfa -order, where alfa is between zero to one. One of the filters is practically implemented and measured.

Darbą atliko Vilniaus Pedagoginio universiteto Socialinių mokslų fakulteto Sociologijos ir Politologijos katedros Politinės sociologijos magistrantūros studentė Nijolė Milašienė. Darbo tema – jaunimo imlumo gandams ypatumai (VPU studentų atveju). Darbo vadovas – prof.habil.dr. V.Pruskus. Darbo apimtis – 60 psl. Darbo tikslas. Atskleisti jaunimo imlumo gandams ypatumus, įtakos veiksnius bei šio reiškinio suvokimą ir vertinimą. Uždaviniai: pateikti gando kaip socialinio reiškinio fenomeno sampratą ir jo interpretacijas įvairiose socialinėse teorijose; išsiaiškinti gando kilimo priežastis ir jo socialinę paskirtį; išnagrinėti visuomenės imlumą gandams aspektus; aptarti veiksnius skatinančius jaunimo imlumo gandams ypatumus; remiantis tyrimu, nustatyti socialinių, ekonomikos ir filosofijos mokslų specialybės studentų imlumo gandams ypatumus, juos sąlygojančius veiksnius ir jų vertinimą. Hipotezės: tikėtina, kad jaunimas domisi gandais, nes jie skatina ieškotis išsamesnės, tikslesnės informacijos – pasitvirtino; imlumą gandams labiausiai įtakoją šeima ir žiniasklaida – pasitvirtino; ekonominiams gandams imlesni ekonomiką studijuojantys studentai negu socialinius mokslus studijuojantys studentai – nepasitvirtino; politiniams gandams imlesni socialinių mokslų studentai negu filosofijos mokslų studentai – nepasitvirtino; gandai reikalingi, nes skatina oficialius informacijos teikėjus teikti visuomenei iššsamesnę ir visapusiškesnę informaciją – pasitvirtino. Tyrimo objektas. Jaunimo... [toliau žr. visą tekstą] / The work was made by Nijolė Milašienė, Political sociology master‘s degree student of VPU Social sciences faculty Sociology and political sciences department. The subject of the work is youth‘s peculiarities in receptivity for the rumours. The director of the work is prof.hab.dr. V.Pruskus. The largeness of the work is 60 pages. The purpose of the investigation is to ascertain the VPU students’ receptivity for the rumours and the factors that influence it with reference to the investigation. For actualising this purpose there were tasks raised: • to represent the rumour’s as the social phenomenon conception and to discuss the interpretations of rumour in different theories; • to represent the causes of raising rumour and the social destination; • to inspect the aspects of society’s receptivity for the rumours; • to analyse the distribution of rumours among youth (students); to ascertain factors that influence youth’s (students’) receptivity for the rumours and to distinguish types that are current among the youth (students). Hypotheses of the investigation: 1. it is probable that rumours stimulate to look for more comprehensive, precise information – was proved; 2. the receptivity for the rumours influence the most family and mass-media – was proved; 3. students that study economics are more receptive for the economical rumours than students that study social sciences – was not proved; 4. social sciences’ students are more receptive for the political rumours than... [to full text]

Os custos de produção de minério de ferro possuem variações de acordo com a especificidade de cada mina. Na fase mina, dois dos maiores custos de produção estão associados aos índices: distância média de transporte e a relação estéril minério. A implantação do projeto de múltiplas minas e correias transportadoras em Itabira visa diminuir os custos associados a estes dois indicadores. O método de alimentação da planta de beneficiamento oriundo de múltiplas minas foca em reduzir a relação estéril minério global do complexo e a implantação de correias transportadoras mitiga o aumento da distância média de transporte. O presente trabalho tem seu enfoque em uma proposta de lavra de múltiplas minas e de uma pilha de minério para alimentação de três diferentes usinas. Propõem-se um modelo de programação linear por metas que determinará a melhor alimentação das usinas, menor distância média de transporte e menor relação estéril minério. Este modelo de otimização foi elaborado utilizando o software LINGO com interface com EXCEL, e avalia cenários diversificados entre o transporte por caminhões fora de estrada e o transporte misto entre caminhões fora de estrada e transportadores de correia de longa distância. Os resultados apresentados mostram que o método de múltiplas minas é uma saída técnica e economicamente viável para melhor aproveitamento das jazidas do Complexo Minerador de Itabira, apresentando uma economia que varia de US$82M até US$118M dependendo do local de instalação das unidades de Britagem Semimóvel (BSMs). / Production costs of iron ore varies according to the specificity of each mine. In the mining phase, some of the largest operational costs are associated to the haulage distance and the stripping ratio. In this context, the implementation of the multiple mines project and the conveyor belts at the Itabira Complex Mines aims to optimize these two indicators. The multiple mines methodology focuses on reducing the overall stripping ratio of the complex, and the implementation of conveyor belts mitigates the increase of the haulage distance. Two mines and a stock pile are available to feed three different concentration plants. The goal is to achieve the best way to feed the plants considering the economic aspects. A linear goal programming model is proposed to determine the best iron ore mass feeding the plants from different mines, taking into account the least haulage distance and the smallest stripping ratio. This optimization model was developed using LINGO Software to interface with EXCEL and evaluate diversified scenarios. The results showed that the method of multiple mines is a technical and economically viable method for mine planning at the Itabira Complex.

Cette thèse porte sur l’étude du comportementdes bandes de convoyeurs soumisesà des contraintes mécanique, thermique et hydrique.La bande est constituée par un renforttextile multi-plis incorporé dans deux couchesde revêtement en caoutchouc. Le matériau dela bande en composite structural a été caractériséexpérimentalement à l'aide des essais mécaniqueset hydriques sur des éprouvettes normaliséesen composites avec et sans couche decaoutchouc. Des essais d’impact sont élaborésà fin d’identifier les différents modesd’endommagement à l’aide des observationsmicroscopiques.Une étude expérimentale est élaborée sur laméthode de réparation de la bande par collagede patchs internes en utilisant deux procédés decollage : la polymérisation à froid et la vulcanisationà chaud. Deux modèles analytiques unidimensionnelet bidirectionnel sont développéset confrontés aux modèles par éléments finispour étudier le comportement hygrothermomécaniquede la bande à l’aide des donnéesde caractérisation expérimentale. Les résultatsont montré que les performances de laméthode de réparation dépendent de différentsparamètres hygro-thermomécaniques et géométriques.Un outil d’aide à l’amélioration et à laconception en tenant compte de ces paramètresest enfin proposé. / This thesis deals with the study of themechanical behavior of a conveyor belt underhydrothermal effects. The structure that hasbeen studied consists of a 4 textile layers boundtogether by a thin rubber adhesive layer andcovered with the rubber cover. The beltcomposite structural was characterized usingstandard specimens with and without rubberlayers under tensile and ageing tests. Impacttests are developed to identify the differentdamage modes using microscopic observations..Experimental study of reparation method waselaborated using two processes: hotvulcanization and cold polymerization. Twoone-dimensional and bidirectional analyticmodels are developed and compared with finiteelement models to study the hygrothermomechanicalbehavior of the belt usingexperimental characterization parameters. Theresults showed that the performance ofreparation method of the belt depends ondifferent parameters. A tool for improvementand designing of the reparation is proposedtaking into account these parameters

This thesis deals with a theoretical and an experimental exploration of squeeze film levitation (SFL) of light objects. The investigations aimed to find the important design parameters controlling this levitation mechanism and also to suggest an alternative way to implement SFL. The study, through computer modelling and experimental validation, focused on Poisson's contraction effect for generating SFL. A finite element model (ANSYS) was verified by experimental testing of five different plate designs. Each plate was subjected to a uniaxial plain stress by an arrangement of two hard piezoelectric actuators (PZT) bonded to the bottom of the plate and driven with DC or AC voltages. It was observed that pulsation of a dimple or crest shaped elastic deformation along the longitudinal axis in the central area of the plate was created because of Poisson's contraction. This Poisson's effect generated the squeeze-film between the plate and the levitated object. The separation distance between a floating lightweight object and the plate was analysed using computational fluid dynamics (ANSYS CFX) through creation of a modelling model for the air-film entrapped between the two interacting surfaces - a typical three-dimensional fluid-solid interaction system (FSI). Additionally, the levitation distance has been experimentally measured by a Laser Sensor. A satisfactory agreement has been found between model predictions and experimental results. Two levitation systems, one based on a horn transducer (Langevin type) and the other one in the form of a plain rectangular plate made of Aluminium and firmly fastened at both ends with a surface-mounted piezoelectric actuator, were compared in this thesis. Both devices were based on SFL mechanism. Evidently, the performances of both designs were greatly influenced by the design structure and in particular by the driving plate characteristics such as plate size and geometry as well as the driving boundary conditions. To this end, physical experiments were carried out and it was found that the device utilising horn-type transducer yields better levitation performance. Ultimately, the research explained the confusion between three approaches to non-contact levitation through literature review and also pointed out some essential parameters like piezoelectric actuators location, material of the driving structure, coupled-field between the actuators and the driving structure and the fluid-solid interface that was existed between the excited plate and the levitated object.

A otimização de processos e a redução de custos são os dois principais fatores que sustentam a competitividade das indústrias atualmente. Diante deste cenário, buscou-se otimizar o processo de fabricação de barras trefiladas de aço mola SAE 9254, através da eliminação do recozimento anterior ao processo de trefilação, por intermédio de um resfriamento controlado no cooling conveyor, na laminação.. Para isso, a taxa de resfriamento do fio-máquina após a laminação foi variada a fim de garantir a homogeneização da dureza ao longo das espiras, característica essa essencial para o processamento na trefila. Além da redução de custos com o recozimento, se o objetivo fosse alcançado, poder-se-ia otimizar o processo de reaquecimento deste aço na laminação. Como resultado, seria possível melhorar a qualidade superficial do fio-máquina e, por conseqüência, aumentar o rendimento metálico do produto, sem que a descarbonetação máxima e média fossem prejudicadas. Os experimentos foram desenvolvidos com base no resfriamento do fio-máquina no cooling conveyor. Durante o processamento na laminação, foi realizada uma amostragem especial a fim de mapear a variação das propriedades ao longo das espiras. Os resultados apontaram que é possível a otimização do processo de fabricação do aço mola SAE 9254, principalmente para a condição de resfriamento na laminação quando utilizado um escalonamento na velocidade de transporte do fio-máquina no cooling conveyor. Este incremento nas velocidades de deslocamento do material, feita através do escalonamento da velocidade, propicia uma alteração nos “pontos quentes” das espiras, gerando uma uniformidade maior em seu resfriamento, garantindo assim, uma homogeneidade nas propriedades mecânicas. / The process optimization and cost reduction are the two main factors that gives sustainability for today industries competitiveness. For this reason, it was attempted to optimize the manufacturing process of cold draw bars of SAE 9254 spring steel by eliminating pre-annealing of wire drawing, through a controlled cooling on the cooling conveyor, in the rolling mill process. For this, the cooling rate of wire rod after rolling process was varied to ensure the homogeneity of hardness along the coil, the essential feature for wire drawing process. In addition to reducing costs annealing, if the purpose was reached, the reheating process would be optimized in the rolling mill. As a result, it would be possible to improve the surface quality of wire rod and, consequently, increase the metallic yield of the product, without the decarburization maximum and average were damaged. The experiments were developed based on wire rod cooling thermograph in the cooling conveyor. During rolling mill processing, special sampling was performed to map the variation of properties along the coils. The results showed that it is possible to optimize the manufacturing process of the SAE 9254 spring steel, mainly for the cooling condition in the rolling process when scaling speeds in wire rod transportation was used on the cooling conveyor. This speed increase of the material transportation, through the scaling speed, provides a change in "hot spots" of the coils, generating a greater uniformity in their cooling, thus ensuring uniformity in mechanical properties.

Public part of this work summarizes theoretical knowledge of industrial visualization from definition of basic concepts to more specific description of the types and possibilities of current visualization. The second part deals with design and creation application for automatic data import and creation of graphic library of symbols conveyor technology for Zenon. To protect know-how of atx – technicka kancelar pro komplexni automatizaci s.r.o. is this part private.

Correias transportadoras têm sido utilizadas como um modo eficiente de transporte de materiais por diversos ramos da indústria. A vida útil desse equipamento é influenciada pelo desgaste natural ocasionado pelo uso excessivo e falhas, tais como rasgos, cortes e perfurações. Nesse trabalho, é proposto um método de identificação de falhas em correia transportadora por meio de processamento digital de imagens, combinadas com técnicas de escaneamento 3D a laser e aprendizado de máquinas (redes neurais e SVM (Support Vector Machine - Máquina de Vetores de Suporte)). A averiguação experimental foi efetuada em duas etapas: a primeira etapa inicia-se com a aquisição, o pré-processamento e a geração do banco de imagens; a segunda, com a extração e a classificação das amostras. O vetor de características foi submetido a dois classificadores: rede neural do tipo Perceptron Múltiplas Camadas (com 15 topologias candidatas) e um classificador SVM, variando sua função kernel: linear, quadrática, polinomial, gaussiano, RBF (Radial-Basis Function - Função de Base Radial) e MLP (Multilayer Perceptron – Perceptron Múltiplas Camadas). Os resultados experimentais mostram que a metodologia proposta obtém uma boa acurácia na estimação das falhas, mostrando-se promissora na tarefa de diagnosticar e classificar falhas em correias transportadoras. / Conveyor belts have been used as an efficient way of transporting materials by various industry branches. This equipment\'s lifespan is influenced by natural wear caused by overuse and flaws, such as tears, cuts, and perforations. This work proposes a method of identifying flaws in the conveyor belt using digital image processing, combined with 3D laser scanning techniques and machine learning (neural networks and SVM - Support Vector Machine). The experimental investigation has been carried out in two stages: the first stage begins with the acquisition, preprocessing, and generation of an image bank; the second, with the extraction and classification of the samples. The characteristic\'s vector has been submitted to two classifiers: Multi-Layer Perceptron neural network (with 15 candidate topologies) and an SVM classifier, varying its kernel function: linear, quadratic, polynomial, Gaussian, RBF (Radial-Basis Function) and MLP (Multilayer Perceptron). The experimental results show that the proposed methodology obtains a good accuracy in the failure estimation, being promising in the task of diagnosing and classifying flaws in conveyor belts.

<p>Normally the operational amplifier is used as a component in active filter design. The goal for future components in filter design is large bandwith and the use of low supply voltages. The use of current-mode instead of voltage-mode circuits gets a step closer to the required performance. A component that use current as the signal conveying part is the current conveyor. In this report a comparative study between two current conveyor structures of second generation (CCII) is performed. The most suited is later implemented and simulated using the CMOS process AMS.C035. The component is also tested in a continuous-time elliptic low-pass filter of leapfrog type. The filter does not behave as it should. However, better performance can be obtained by redesigning the current conveyor.</p>