36 resultados para Box-columns
Resumo:
Stratigraphic Columns (SC) are the most useful and common ways to represent the eld descriptions (e.g., grain size, thickness of rock packages, and fossil and lithological components) of rock sequences and well logs. In these representations the width of SC vary according to the grain size (i.e., the wider the strata, the coarser the rocks (Miall 1990; Tucker 2011)), and the thickness of each layer is represented at the vertical axis of the diagram. Typically these representations are drawn 'manually' using vector graphic editors (e.g., Adobe Illustrator®, CorelDRAW®, Inskape). Nowadays there are various software which automatically plot SCs, but there are not versatile open-source tools and it is very di cult to both store and analyse stratigraphic information. This document presents Stratigraphic Data Analysis in R (SDAR), an analytical package1 designed for both plotting and facilitate the analysis of Stratigraphic Data in R (R Core Team 2014). SDAR, uses simple stratigraphic data and takes advantage of the exible plotting tools available in R to produce detailed SCs. The main bene ts of SDAR are: (i) used to generate accurate and complete SC plot including multiple features (e.g., sedimentary structures, samples, fossil content, color, structural data, contacts between beds), (ii) developed in a free software environment for statistical computing and graphics, (iii) run on a wide variety of platforms (i.e., UNIX, Windows, and MacOS), (iv) both plotting and analysing functions can be executed directly on R's command-line interface (CLI), consequently this feature enables users to integrate SDAR's functions with several others add-on packages available for R from The Comprehensive R Archive Network (CRAN).
Resumo:
Ion Mobility Spectrometry coupled with Multi Capillary Columns (MCC -IMS) is a fast analytical technique working at atmospheric pressure with high sensitivity and selectivity making it suitable for the analysis of complex biological matrices. MCC-IMS analysis generates its information through a 3D spectrum with peaks, corresponding to each of the substances detected, providing quantitative and qualitative information. Sometimes peaks of different substances overlap, making the quantification of substances present in the biological matrices a difficult process. In the present work we use peaks of isoprene and acetone as a model for this problem. These two volatile organic compounds (VOCs) that when detected by MCC-IMS produce two overlapping peaks. In this work it’s proposed an algorithm to identify and quantify these two peaks. This algorithm uses image processing techniques to treat the spectra and to detect the position of the peaks, and then fits the data to a custom model in order to separate the peaks. Once the peaks are separated it calculates the contribution of each peak to the data.
Resumo:
Simulated moving bed (SMB) chromatography is attracting more and more attention since it is a powerful technique for complex separation tasks. Nowadays, more than 60% of preparative SMB units are installed in the pharmaceutical and in the food in- dustry [SDI, Preparative and Process Liquid Chromatography: The Future of Process Separations, International Strategic Directions, Los Angeles, USA, 2002. http://www. strategicdirections.com]. Chromatography is the method of choice in these ¯elds, be- cause often pharmaceuticals and ¯ne-chemicals have physico-chemical properties which di®er little from those of the by-products, and they may be thermally instable. In these cases, standard separation techniques as distillation and extraction are not applicable. The noteworthiness of preparative chromatography, particulary SMB process, as a sep- aration and puri¯cation process in the above mentioned industries has been increasing, due to its °exibility, energy e±ciency and higher product purity performance. Consequently, a new SMB paradigm is requested by the large number of potential small- scale applications of the SMB technology, which exploits the °exibility and versatility of the technology. In this new SMB paradigm, a number of possibilities for improving SMB performance through variation of parameters during a switching interval, are pushing the trend toward the use of units with smaller number of columns because less stationary phase is used and the setup is more economical. This is especially important for the phar- maceutical industry, where SMBs are seen as multipurpose units that can be applied to di®erent separations in all stages of the drug-development cycle. In order to reduce the experimental e®ort and accordingly the coast associated with the development of separation processes, simulation models are intensively used. One impor- tant aspect in this context refers to the determination of the adsorption isotherms in SMB chromatography, where separations are usually carried out under strongly nonlinear conditions in order to achieve higher productivities. The accurate determination of the competitive adsorption equilibrium of the enantiomeric species is thus of fundamental importance to allow computer-assisted optimization or process scale-up. Two major SMB operating problems are apparent at production scale: the assessment of product quality and the maintenance of long-term stable and controlled operation. Constraints regarding product purity, dictated by pharmaceutical and food regulatory organizations, have drastically increased the demand for product quality control. The strict imposed regulations are increasing the need for developing optically pure drugs.(...)
Resumo:
A capacidade de prever precisamente a produção de energia renovável é extremamente relevante tanto do ponto de vista económico como para controlo da estabilidade da rede elétrica. Para tal, é necessário realizar uma previsão das condições meteorológicas adjacentes à produção de energia a partir de fontes de energia renovável. Vários modelos de previsão têm sido utilizados para este fim, desde modelos atmosféricos a modelos estatísticos, onde se destacam métodos como Redes Neuronais Artificiais ou a Metodologia de Box & Jenkins. Lidar com dados meteo-rológicos pode revelar algumas complicações devido à possível instabilidade das medições, com-plicando o desenvolvimento de um modelo de previsão adequado. Neste trabalho pretende-se realizar a previsão de produção a partir de uma instalação fotovoltaica e um gerador eólico através do uso da Metodologia de Box & Jenkins para desenvolver um modelo capaz de realizar a previsão das condições meteorológicas para diferentes horizontes temporais medidos no topo do edifício do Departamento de Engenharia Eletrotécnica (DEE) da Faculdade de Ciências e Tecnologia (FCT), Universidade Nova de Lisboa (UNL), e usando esses valores para calcular a produção de energia. Os resultados obtidos revelaram um bom desempenho quando comparados os resultados previstos com os resultados reais para o mesmo período de tempo, garantindo que podem ser utilizados para calcular a previsão de potência produzida através das instalações presentes no local e encorajando novos estudos no tema.
Resumo:
This thesis proposes a Monte Carlo valuation method for Worst-of Auto-callable equity swaps. The valuation of this type of swap usually requires complex numerical methods which are implemented in “black-box” valuation systems. The method proposed is an alternative benchmark tool that is relatively simple to implement and customize. The performance of the method was evaluated according to the variance and bias of the output and to the accuracy when compared to a leading valuation system in the market.
Resumo:
A PhD is like a box of chocolates, …… and in this thesis I will present what I got. My work has been focused on a cellular structure that is essential for accurate genome inheritance: the centromere. Centromeres are chromosomal domains that do not rely on the presence of any specific DNA sequence. Rather, they are determined by the presence of a histone variant called CENP-A. Stable transmission of CENP-A containing chromatin is accomplished through 1) an unusually high level of protein stability, 2) selfdirected recruitment of nascent CENP-A near existing molecules, and 3) strict cell cycle regulation of assembly. Together, these features lead to a self-sustaining loop that allows for epigenetic maintenance of centromeres.(...)