958 resultados para Factor analytical method
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The constant evolution of science and the growing demand for new technologies have led to new techniques in instrumentation that can improve detection, separation, resolution, and peak capacity. Comprehensive two-dimensional liquid chromatography (LC×LC) is presented as a powerful tool in complex sample analyses. During an analysis, a sample is subjected to two independent separation mechanisms that are combined, resulting in increased resolving power. For appropriate application of LC×LC, understanding the influence of parameters that require optimization is necessary. The main purpose of optimization is to predict the combination of stationary phases, separation conditions, and instrumental requirements to obtain the best separation performance. This review discusses theoretical, intrumental, and chemometric aspects of LC×LC and focuses on its applications in foods. It aims to provide a clear understanding of the aspects that can be used as strategies in the optimization of this analytical method.
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This study presents an automatic, computer-aided analytical method called Comparison Structure Analysis (CSA), which can be applied to different dimensions of music. The aim of CSA is first and foremost practical: to produce dynamic and understandable representations of musical properties by evaluating the prevalence of a chosen musical data structure through a musical piece. Such a comparison structure may refer to a mathematical vector, a set, a matrix or another type of data structure and even a combination of data structures. CSA depends on an abstract systematic segmentation that allows for a statistical or mathematical survey of the data. To choose a comparison structure is to tune the apparatus to be sensitive to an exclusive set of musical properties. CSA settles somewhere between traditional music analysis and computer aided music information retrieval (MIR). Theoretically defined musical entities, such as pitch-class sets, set-classes and particular rhythm patterns are detected in compositions using pattern extraction and pattern comparison algorithms that are typical within the field of MIR. In principle, the idea of comparison structure analysis can be applied to any time-series type data and, in the music analytical context, to polyphonic as well as homophonic music. Tonal trends, set-class similarities, invertible counterpoints, voice-leading similarities, short-term modulations, rhythmic similarities and multiparametric changes in musical texture were studied. Since CSA allows for a highly accurate classification of compositions, its methods may be applicable to symbolic music information retrieval as well. The strength of CSA relies especially on the possibility to make comparisons between the observations concerning different musical parameters and to combine it with statistical and perhaps other music analytical methods. The results of CSA are dependent on the competence of the similarity measure. New similarity measures for tonal stability, rhythmic and set-class similarity measurements were proposed. The most advanced results were attained by employing the automated function generation – comparable with the so-called genetic programming – to search for an optimal model for set-class similarity measurements. However, the results of CSA seem to agree strongly, independent of the type of similarity function employed in the analysis.
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A simple analytical method for quantification of atenolol in pharmaceutical formulations by diffuse reflectance spectroscopy is described. The method is based on the reaction, on the filter paper surface, between the drug and p-chloranil producing a colored compound. The best reaction conditions were obtained with 20 µL of atenolol solution and 20 µL of p-chloranil. All reflectance measurements were carried out at 550 nm and the linear range was from 1.13x10-2 to 7.88x10-2 mol L-1 (r = 0.9992). The limit of detection was 2.80 x 10-3 mol L-1. The proposed method was successfully applied to analysis of different commercial brands of pharmaceutical formulations and the results obtained by the proposed method were in good agreement with those obtained using the British Pharmacopoeia method.
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Poetics and Politics. AugustoBoal and the Theatre of the Oppressed deals with the ideas and methods of the Brazilian author, director and theatre theorist Augusto Boal. The main purpose of the thesis is to give a description of what can be characterized as the poetics of Augusto Boal. What is the specific nature of his theatre methods and in what way do they differ from traditional theatre? How do these methods actually work? What is the overall intention of the Theatre of the Oppressed? As objects for my research I have selected Forum Theatre and Rainbow of Desire. The reason for this choice is partly that the two methods mentioned have become the most widespread among Boal's theatre forms, partly that they complement each other, the former being a method that works with problems of the material world, in realistic action-based narratives; the latter being an expressionistic analytical method, designed to deal with psychological problems and internalized oppression. Going from a micro- to a macro-level, I first examine the theatrical text of both forms, which in this case includes not only the verbal narrative, but also the performance itself and the setting of it, and even the implied conditions of the whole theatrical situation. Secondly, I turn to the encounter between the text and its actual recipient in the theatrical space. What happens, psychologically, when the observing, but passive spectator is turned into the actor of the play? Thirdly, I discuss the ideological and political implications of the Theatre ofthe Oppressed in real life. The way I interpret Boal's poetics, this is of vital importance. The purpose of the Theatre of the Oppressed is not anything resembling l'art pour l'art. In the contrary, its intention is to teach the oppressed the use of theatre as a martial art, so that they can fight and break the oppression in a social context of the real world. Thus the title Poetics and Politics.
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This book is dedicated to celebrate the 60th birthday of Professor Rainer Huopalahti. Professor Rainer “Repe” Huopalahti has had, and in fact is still enjoying a distinguished career in the analysis of food and food related flavor compounds. One will find it hard to make any progress in this particular field without a valid and innovative sample handling technique and this is a field in which Professor Huopalahti has made great contributions. The title and the front cover of this book honors Professor Huopahti’s early steps in science. His PhD thesis which was published on 1985 is entitled “Composition and content of aroma compounds in the dill herb, Anethum graveolens L., affected by different factors”. At that time, the thesis introduced new technology being applied to sample handling and analysis of flavoring compounds of dill. Sample handling is an essential task that in just about every analysis. If one is working with minor compounds in a sample or trying to detect trace levels of the analytes, one of the aims of sample handling may be to increase the sensitivity of the analytical method. On the other hand, if one is working with a challenging matrix such as the kind found in biological samples, one of the aims is to increase the selectivity. However, quite often the aim is to increase both the selectivity and the sensitivity. This book provides good and representative examples about the necessity of valid sample handling and the role of the sample handling in the analytical method. The contributors of the book are leading Finnish scientists on the field of organic instrumental analytical chemistry. Some of them are also Repe’ s personal friends and former students from the University of Turku, Department of Biochemistry and Food Chemistry. Importantly, the authors all know Repe in one way or another and are well aware of his achievements on the field of analytical chemistry. The editorial team had a great time during the planning phase and during the “hard work editorial phase” of the book. For example, we came up with many ideas on how to publish the book. After many long discussions, we decided to have a limited edition as an “old school hard cover book” – and to acknowledge more modern ways of disseminating knowledge by publishing an internet version of the book on the webpages of the University of Turku. Downloading the book from the webpage for personal use is free of charge. We believe and hope that the book will be read with great interest by scientists working in the fascinating field of organic instrumental analytical chemistry. We decided to publish our book in English for two main reasons. First, we believe that in the near future, more and more teaching in Finnish Universities will be delivered in English. To facilitate this process and encourage students to develop good language skills, it was decided to be published the book in English. Secondly, we believe that the book will also interest scientists outside Finland – particularly in the other member states of the European Union. The editorial team thanks all the authors for their willingness to contribute to this book – and to adhere to the very strict schedule. We also want to thank the various individuals and enterprises who financially supported the book project. Without that support, it would not have been possible to publish the hardcover book.
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Tutkielman tarkoitus oli selvittää, mitkä tekijät määrittelevät kansainvälistymisprosessin potentiaalista menestyjää. Aihetta on tutkittu paljon, mutta laajempi kokonaiskuva kansainvälistymisen menestystekijöistä puuttui. Tutkielman näkökulma on holistinen: Siinä yhdistettiin useampi linssi eri näkökulmia menestymiseen kansainvälistymisessä ja eri tutkimusmetodeja kvalitatiivisista kvantitatiivisiin. Tutkimuksessa käytettiin teoriasidonnaista lähestymistapaa ja konstruktiivista tutkimusotetta, jonka avulla Finpro ry:lle rakennettiin usean tutkimusvaiheen aikana potentiaalisia menestystapauksia tunnistava työkalu. Tutkimus toteutettiin neljässä vaiheessa, joissa rakennettiin kunkin vaiheen testituloksien mukainen konstruktio. Ensimmäisessä vaiheessa teemahaastattelulla selvitettiin konstruktion tarvepohja sekä rajaehdot. Konstruktion pohjaksi taulukoitiin 2001–2012 vuosien tutkimuksien tutkituimmat menestystekijät ja siihen lisättiin kansainvälistymisprosessin asiantuntijoiden korostamat menestystekijät. Tulokset yhdistettiin rakentamalla Konstruktio1. Toisessa vaiheessa Konstruktio1:sta kyselyn ja eksploratiivisen faktorianalyysin avulla faktoroitiin tärkeimmät menestymisen taustalla olevat ilmiöt, joista rakennettiin Konstruktio2. Kolmannessa vaiheessa kahden riippumattomien otosten ttestin avulla selvitettiin, mitkä Konstruktio2:n menestysfaktorit ovat tärkeimpiä ICT- ja life science -toimialoilla toimiville yrityksille ja mitä ilmiöitä yrityksen johto tai sijoittajat pitävät tärkeinä. Tuloksien pohjalta Konstruktio2 kehitettiin Konstruktio3:ksi. Neljännessä vaiheessa Konstruktio3:n pätevyyttä testattiin peilaamalla sen menestysfaktoreita kuuteen menestyjiksi todettuun tapaukseen, ja sen toimivuus selvitettiin kuuden avoimen haastattelun avulla. Tuloksien avulla Konstruktio3:sta rakennettiin Konstruktio4. Tutkimukset osoittivat, että menestystekijät vaihtelevat yrityksen kansainvälistymispolun ja eri näkökulmien mukaan. Tutkimus loi vahvan teoreettisen ja liiketoiminnallisen kontribuution. Tutkimusvaiheiden avulla hahmotettiin kansainvälistymisessä menestymisen kokonaisuus ja luottiin uusi näkemys pk-yrityksen menestymisestä. Toisaalta päästiin myös heti käyttövalmiiseen lopputulokseen, joka auttaa Finpron konsultteja ja myyjiä ymmärtämään menestymistä kansainvälistymisprosessissa ja löytämään potentiaalisia menestyjiä.
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Due to the large amount of pesticides applied in agriculture, mainly herbicides, there is a growing concern about a possible environmental contamination with these products, including water bodies. Given the above, the aim of the present work was to detect and quantify herbicides through multiresidue analysis in water samples collected in semi-artesian wells and springs in a rural area of the city of Jaboticabal (SP). Samples were collected from 32 wells and 13 water springs, in three different seasons: October 2010, February 2011 and May 2011. Additionally, samples at a residence in the urban area were also collected. Analysis using high performance liquid chromatography coupled to mass spectrometry was performed and herbicides ametryn, amicarbazone, clomazone, diclosulan, diuron, hexazinone, imazapic, imazapyr, isoxaflutole, S-metolachlor, sulfentrazone, sulfometuron-methyl, and tebuthiuron were evaluated. In semi-artesian wells, an incresed quantity of herbicides was found in comparison with the water springs. Among the tested herbicides, hexazinone, imazapyr and sulfentrazone were detected in measurable amounts in accordance with the analytical method applied, while clomazone was the most common herbicide being detected in more than 60% of the samples. Ametryn, diuron and amicarbazone herbicides were also detected. Diclosulan, imazapic, isoxaflutole, S-metolachlor, sulfometuron-methyl, and tebuthiuron were not detected in any sample. Inappropriate use of these products without prior knowledge of the behavior of the soil can lead to groundwaters and water springs contamination, thus an ongoing monitoring of this resource becomes very important.
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This study has aimed to develop a method for simultaneous extraction and determination by liquid chromatography and mass spectrometry (LC-MS/MS) of glyphosate, aminomethylphosphonic acid (AMPA), shikimic acid, quinic acid, phenylalanine, tyrosine and tryptophan. For the joint analysis of these compounds the best conditions of ionization in mass spectrometry and for chromatographic separation of the compounds were selected. Calibration curves and linearity ranges were also determined for each compound. Different extraction systems of the compounds were tested from plant tissues collected from sugarcane (Saccharum officinarum) and eucalyptus (Eucalyptus urophylla platiphylla) plants two days after the glyphosate application at the dose of 720 g a.e. ha-1. The plant material was dried in a forced air circulation drying oven and in a lyophilizer, and subsequently the extractions with acidified water (pH 2.5), acetonitrile-water (50:50) [v/v] and methanol-water (50:50) [v/v] were tested. To verify the recovery of the compounds in the plant matrix with acidified water as an extracting solution, the samples were fortified with a solution containing the mixture of the different analytical standards present so that this one presented the same levels of 50 and 100 μg L-1 of each compound. All experiments were conducted with three replicates. The analytical method developed was efficient for compounds quantifications. The extraction from the samples dried in an oven and using acidified water allowed better extraction levels for all compounds. The recovery levels of the compounds in the fortified samples with known amounts of each compound for both plants samples were rather satisfactory.
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Tutkimuksen tarkoituksena oli kartoittaa lämpötilan vaikutusta veden orgaanisten haitta-aineiden hapetuksessa PCD-menetelmällä. Kokeita tehtiin näytteiden eri alkulämpötiloilla. Malliyhdisteenä kokeissa käytettiin oksaalihappoa. Teoriaosuudessa käsiteltiin pulssittaista koronapurkausta ilmiönä. Lisäksi tarkasteltiin, kuinka PCD-menetelmällä muodostuu hapettimia neste-kaasufaasissa. Syntyvistä hapettimista keskityttiin otsoniin ja hydroksyyliradikaaliin. Kokeellisessa osuudessa esiteltiin käytetty PCD-laitteisto. Esittelyn jälkeen siirryttiin hapetuskokeiden kuvaamiseen ja analyysin suorittamiseen titrauksella. Lopuksi koottiin tulokset. Tutkimuksissa prosessin hapetustehon havaittiin heikentyvän lämpötilan noustessa tutkitulla lämpötila-alueella, mikä voi selittyä kaasufaasissa muodostuvan otsonin heikentyvällä liukoisuudella. Tuloksia voidaan pitää viitteellisinä, ja selkeän mallin muodostamiseksi tarvitaan jatkotutkimuksia laajemmalla lämpötila-alueella tarkasti toistettavilla koejärjestelyillä.
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Analytical calculation methods for all the major components of the synchronous inductance of tooth-coil permanentmagnet synchronous machines are reevaluated in this paper. The inductance estimation is different in the tooth-coil machine compared with the one in the traditional rotating field winding machine. The accuracy of the analytical torque calculation highly depends on the estimated synchronous inductance. Despite powerful finite element method (FEM) tools, an accurate and fast analytical method is required at an early design stage to find an initialmachine design structure with the desired performance. The results of the analytical inductance calculation are verified and assessed in terms of accuracy with the FEM simulation results and with the prototype measurement results.
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Työn tarkoituksena oli löytää pyörivien koneiden ruuviliitosten mitoittamiseen parhaiten soveltuva ja kansainvälisesti tunnettu laskentamenetelmä. Tavoitteena oli laatia luotettava mitoitusohjelma, jota käyttämällä suunnittelijoiden työ nopeutuu ja tulokset ovat yhtenäisiä. Työssä vertaillaan pääasiassa standardien EN 1993-1-8 ja VDI 2230 mukaisia ruuviliitosten mitoitusmenetelmiä. Vertailun perusteella standardin VDI 2230 mukainen systemaattinen laskentamenetelmä soveltuu sähkökoneiden vääntöä välittävien ruuviliitosten mitoittamiseen analyyttisistä menetelmistä parhaiten. Laadittu mitoitusohjelma mitoittaa yksittäisen ruuviliitoksen standardin VDI 2230 mukaisesti, antaen tulokseksi lujuustarkasteluraportin. Lujuustarkasteluraportista käy ilmi projektin tiedot, mitoituksen lähtötiedot, lujuustarkastelut, esikiristysmomentti ja kierteen toiminnallisen osan vähimmäispituus. Kehitetty mitoitusohjelma antaa johdonmukaisia tuloksia, mutta ruuvin nimellisulkohalkaisijan automaattinen valinta ei aina mitoita ruuvia riittävän suureksi, jolloin ruuvin nimellisulkohalkaisija on määritettävä manuaalisesti. Ohjelman käyttäminen on suoraviivaista ja nopeaa kun mitoitetaan pyörähdyssymmetrisiä laippaliitoksia, joihin vaikuttaa ainoastaan vääntömomentti. Jos liitokseen vaikuttaa ruuvien pituusakselien suuntainen voima, on liitoksen pelkistäminen yksittäisestä ruuvista koostuvaksi liitokseksi vaikeampaa ja pelkistämiseen saatetaan tarvita elementti-menetelmää.
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Tomatoes are highly susceptible to fungi contamination in the field, during transportation, processing, and storage. Aspergillus flavus and Aspergillus parasiticus have been isolated from tomatoes and tomato products, and both fungi species can produce aflatoxin, mycotoxin with hepatotoxic, carcinogenic, teratogenic, and mutagenic effects on all animal species tested so far. In order to verify a possible aflatoxin contamination of tomato products commercialized in Brazil, 63 samples of tomato products (pulp, paste, purée, ketchup, dehydrated tomatoes, and dried tomatoes preserved in oil) produced in 5 Brazilian states and 1 imported sample (ketchup), totalizing 29 brands, were analyzed by thin layer chromatography. The analytical method showed an average recovery of 86% for all aflatoxins at two spiking levels. The limits of detection for the aflatoxins B1, B2, G1, and G2 varied with the type of the product ranging from 2 to 7 µg/kg. Aflatoxins were not detected in any evaluated sample indicating that they did not pose a risk to human health since there was no invasion of raw materials by toxigenic fungi or no conditions for toxin production.
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This study aimed to quantify the levels of catechins and caffeine in various forms of presentation of green tea: infusion tea bags, extract, and ready-to-drink beverage and, based on their content, identify the most suitable for consumption. High Performance Liquid Chromatography (HPLC) analytical method was used for the quantification of catechins and caffeine. The tea bags had the highest concentration of total catechins with 5 to 9.5% followed by the extract with 3.64 to 4.88%, and ready-to-drink green tea beverage showed low levels of catechins, from 0.14 to 0.26%. As for caffeine content, green tea extract had higher concentration (1.96 to 3.54%) compared to the tea bags (1.39 to 1.57%). Tea bags were found the most suitable for consumption because it contains higher amounts of catechins and smaller amounts of caffeine.
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Tämän diplomityön tavoitteena on kehittää sopiva analyyttinen menetelmä muokatun kraft-sellukuidun substituutioasteen (DS) kvantitatiivista määrittämistä varten. Muokkauksella tarkoitetaan tässä yhteydessä joko kovalenttisesti tai adsorption avulla tapahtuvaa molekyylin kiinnittymistä sellukuidun pinnalle. Työn kirjallisuusosuudessa käsitellään lyhyesti eri muokkaustapoja ja yhdisteitä joiden avulla voidaan saavuttaa haluttuja ominaisuuksia sellusta valmistetuille lopputuotteille. Lisäksi kirjallisuusosuudessa käydään läpi käyttötarkoitukseen soveltuvimpia suoria ja epäsuoria analyysimenetelmiä. Analyysimenetelmistä kaikkein lupaavimpia testattiin työn kokeellisessa osassa. Diplomityön kokeellisessa osassa keskityttiin kehittämään muokatulle sellulle kvantitatiivista menetelmää DS:n määrittämiseksi Fourier-muunnos infrapuna-vaimennettu kokonaisheijastus (FTIR-ATR) spektrometrillä. Kirjallisuuskatsauksessa ei löytynyt yhtään dokumentoitua tutkimusta, jossa FTIR-ATR menetelmää olisi käytetty muokatun sellukuidun kvantitatiiviseen tutkimukseen. Muiden analyysimenetelmien, kuten alkuaineanalyysin, termogravimetrisen analyysin (TGA) ja valomikroskopian avulla pyrittiin tuottamaan lisätietoa muokkauksesta. Kvantitatiivisen FTIR-ATR menetelmän kehitykseen käytetyt muokatut sellukuidut olivat selluloosa-asetaattia ja selluloosa betainaattia. Saatujen tulosten perusteella muokattujen sulfiitti- ja kraft sellukuitujen DS:n kvantitatiivinen määrittäminen on mahdollista FTIR-ATR menetelmällä. Vähäinen kalibrointipisteiden määrä vaikeutti tarkan analyysimenetelmän tekemistä. Kehitetyn menetelmän suurimpina ongelmina olivat kiinteiden näytteiden heterogeenisyys sekä mahdollisten epäpuhtauksien tunnistaminen. Jatkotutkimusten avulla kehitettyä menetelmää on kuitenkin mahdollista käyttää muokattujen sellukuitujen jatkuvaan analysointiin selluteollisuudessa.
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This qualitative study examined resilience factors of eight university and college students with learning disabilities as revealed through retrospective interviews. This study has added to the existing literature surrounding resilience especially as it relates to individuals with learning disabilities. This study may provide additional insight into the emotional impacts of repeated and chronic risks on students with learning disabilities. The major themes that emerged using the interpretive phenomenological analysis method (Smith & Osborn, 2003) were organized under these four major headings: Challenges and Obstacles, Surviving Challenges, Supportive Conditions, and A Journey of Discovery and Hope. An adaptation of the listening guide analytical method (Gilligan, Spencer, Weinberg, & Bertsch, 2003) was also utilized and offered a more personal depiction of the participants and an exploration of the unique contributions their stories made to this study. Specifically, a theme of feeling trapped/wanting to escape emerged as a reaction to adversity faced during elementary school years. Furthennore, this study has demonstrated that for several of the participants, the benefits of positive outlets extended beyond nurturing areas of strength and self-esteem to also include the provision of a short respite from their challenges and enhanced feelings of overall well-being. Additionally, this study may add to the existing literature surrounding character traits evident in resilient students, specifically highlighting the significance of optimism and selfacceptance.