998 resultados para Duo Elina Järvelä
Resumo:
This paper describes the development of a methodology for solid phase extraction (SPE) and pre-concentration of nitrosamines from aqueous samples using granular activated charcoal as stationary phase. micelar electrokinetic capillary Chromatography (MEKC) was used for the separation and identification of the nitrosamines in the extracts. Using a sample with 50 µg l-1 of each nitrosamines standards (dimethylnitrosamine, DMN; diethylnitrosamine, DEN; N-nitrosopyrrolidine, NPYR; N-nitrosopiperidine, NPIP; N-nitrosomorpholine, NMOR), the methodology showed a range of recuperation from 29 to 107% with a linear zone between 10 and 500 µg l-1. The developed methodology can be applicable to the determination of these analytes in different aqueous samples.
Resumo:
The main purpose of this work is the identification and quantification of phenolic compounds in coal tar samples from a ceramics factory in Cocal (SC), Brazil. The samples were subjected to preparative scale liquid chromatography, using Amberlyst A-27TM ion-exchange resin as stationary phase. The fractions obtained were classified as "acids" and "BN" (bases and neutrals). The identification and quantification of phenols, in the acid fraction, was made by gas chromatography coupled to mass spectrometry (GC/MS). Nearly twenty-five phenols were identified in the samples and nine of them were also quantified. The results showed that coal tar has large quantities of phenolic compounds of industrial interest.
Resumo:
The goal of this article is to discuss the application of comprehensive two-dimensional gas chromatography (GCxGC) to petrochemical samples. The use of GCxGC for petroleum and petroleum derivatives characterization, through group type analysis, or BTEX (benzene, toluene, ethylbenzene, xylenes), total aromatic hydrocarbons, polyaromatic hydrocarbons, sulfur-containing, oxygen-containing, and nitrogen-containing compounds is presented. The capability of GCxGC to provide additional specific chemical information regarding petroleum processing steps, such as dehydrogenation of linear alkanes, the Fischer-Tropsch process, hydrogenation and oligomerization is also described. In addition, GCxGC analyses of petrochemical biomarkers and environmental pollutants derived from petrochemicals are reported.
Resumo:
Anaerobisissa olosuhteissa muodostuva rikkivetykaasu on tyypillinen ongelma etenkin pitkill paineviemriosuuksilla. Sille ominainen epmiellyttv haju aiheuttaa jtevedenksittelyverkostoissa ja viemrilinjojen lhialueilla merkittvi hajuongelmia. Lisksi rikkivedyn hapettuessa rikkihapoksi viemri joutuu alttiiksi korroosiolle. Helsingin Etel rannassa sijaitsevaan Munkkisaareen ptyy 4,4 km pitk paineviemri. Viemrin tuuletusputken kautta leviv rikkivety on aiheuttanut hajuongelmia alueella. Korkeimmat mitatut rikkivetypitoisuudet tuuletusputken lheisyydess olivat jopa 300 ppm. Tutkimuksessa tehtiin koeajoja erilaisilla hajunpoistokemikaaleilla rikkivetyongelman ratkaisemiseksi. Viemriin annosteltiin sen alkupss jatkuvatoimisesti ferrosulfaattia ja ferrinitraattisulfaattia, sek shokki-ksittelyll natriumhydroksidia (lipe). Munkkisaaressa mitatut rikkivetypitoisuudet osoittivat kytettyjen kemikaalien tehokkuuden rikkivedyn poistossa. Rikkivedyn saostamiseen tarkoitetut rautasuolat (ferrosulfaatti ja ferrinitraattisulfaatti) vhensivt 100 - 150 g annoksilla rikkivety yli 90 prosenttia. Natriumhydroksin annoksella 3600 g/m viemrin mikrobiologinen toiminta voitiin est keskimrin kymmeneksi pivksi, mutta tehokas rikkivedyn muodostumisen esto vaatisi ksittelyn uusimisen noin 5 pivn vlein. Normaaleissa viemrin olosuhteissa rikkivety muodostui vuorokauden aikana yht nelimetri kohden noin 10 g. Kemikaaliksittelyjen avulla muodostuminen aleni parhaimmillaan kymmenesosaan alkuperisest. Tulosten perusteella kemikaalien kytll viemriss voisi vltty kalliilta saneeraukselta Munkkisaaressa sek muissa korroosiolle alttiiksi joutuvissa viemreiss. Kemikalointikustannukset rautasuoloilla olivat noin 11 000 - 34 000 ja lipell noin 7 000 vuodessa.
Resumo:
Comprehensive Multidimensional Chromatography is a relatively new analytic technique, which is receiving growing attention in many parts of the world, including recently in Brazil. This work presents terms in Portuguese which are commonly used in Comprehensive Multidimensional Chromatography in order to help standardize the vocabulary employed in this area in the scientific literature. It also includes some symbols, their nominations, and explanation of some terms, whenever necessary. This proposal does not intend to be comprehensive or definitive; on the contrary, it intends to be a first step in the process of establishing a standardized nomenclature, serving as a base for a further sound discussion in the scientific community realm.
Resumo:
Background: Myeloid cells are key players in the recognition and response of the host against invading viruses. Paradoxically, upon HIV-1 infection, myeloid cells might also promote viral pathogenesis through trans-infection, a mechanism that promotes HIV-1 transmission to target cells via viral capture and storage. The receptor Siglec-1 (CD169) potently enhances HIV-1 trans-infection and is regulated by immune activating signals present throughout the course of HIV-1 infection, such as interferon (IFN). Results: Here we show that IFN-activated dendritic cells, monocytes and macrophages have an enhanced ability to capture and trans-infect HIV-1 via Siglec-1 recognition of viral membrane gangliosides. Monocytes from untreated HIV-1-infected individuals trans-infect HIV-1 via Siglec-1, but this capacity diminishes after effective antiretroviral treatment. Furthermore, Siglec-1 is expressed on myeloid cells residing in lymphoid tissues, where it can mediate viral trans-infection. Conclusions: Siglec-1 on myeloid cells could fuel novel CD4+ T-cell infections and contribute to HIV-1 dissemination in vivo.
Resumo:
The development of analytical methods for determination of eight pesticides of different chemical classes (trichlorfon, propanil, fipronil, propiconazole, trifloxystrobin, permethrin, difenoconazole and azoxystrobin) in sediments with gas chromatography-micro-electron capture detector (GC/ECD) and comprehensive two-dimensional gas chromatography with micro-electron capture detector (GCxGC/ECD) is described. These methods were applied to real sediment samples, and the best results were obtained using a 5% diphenyl-methylpolysiloxane column for 1D-GC. For GCxGC the same column was employed in the first dimension and a 50%-phenyl-methylpolysiloxane stationary phase was placed in the second dimension. Due to the superior peak capacity and selectivity of GCxGC, interfering matrix peaks were separated from analytes, showing a better performance of GCxGC.
Resumo:
Tavoitteeni tss tutkimuksessa oli selvitt, miten kirjallisuustieteellisi proosa-anayysin ksitteit opetetaan opetussuunnitelman mukaisissa lukion idinkielen ja kirjallisuuden oppikirjoissa ja miten hyvin kokelaat hallitsivat kertoja-ksitteen tekstitaidon ylioppilaskokeessa kevll 2007. Samalla pohdin, minklainen kirjallisuustieteellinen ksitteist palvelisi tekstianalyysin opetusta koulussa, koska Lukion opetussuunnitelman perusteet 2003 ja idinkielen ylioppilaskoe edellyttvt idinkielen ja kirjallisuuden opetukselta ja oppilailta ksitteiden kytt. Tutkimusaineistonani olivat kaikki kuusi kytss olevaa lukion idinkielen ja kirjallisuuden oppikirjaa ja 440 kpl kevn 2007 idinkielen tekstitaidon ylioppilaskokeen vastausteksti. Oppikirjoja tarkastelin soveltamalla niiden arviointiin Lev S. Vygotskin ajatuksia arkiksitteiden ja tieteellisten ksitteiden opettamisesta ja Hans Aeblin esittmi teoreettisia malleja ksitteiden opettamisesta ja oppimisesta. Tutkimukseni osoittaa, ett opetussuunnitelmassa mainittujen proosa-analyysin ksitteiden kertoja, nkkulma, motiivi, aihe ja teema opetus on eptsmllist. Oppikirjoissa ei ole otettu huomioon sit, ett ksitteenoppiminen on monivaiheinen prosessi. Myskn problematiikkaa, joka aiheutuu kyseisten ksitteiden mrittelyn kirjavuudesta ja kytst sek arkikielen ksittein ett tieteellisin ksittein, ei oppikirjoissa ksitell. Sama nkyy ylioppilaskoeaineistossa: oppilaat eivt hallitse ksitett kertoja tieteellisen ksitteen. Tietoisuus kirjallisuustieteellisten ksitteiden mrittelyn problematiikasta ja arkiksitteiden ja tieteellisten ksitteiden ontologisista kategorioista on onnistuneen ksitteenoppimisen edellytys. Kirjallisuustieteelliset ksitteet ovat metaksitteit, jotka edellyttvt oppilaiden metaksitteellisen tietoisuuden ja motivaation hydyntmist opetuksessa, jossa olisi sovellettava monipuolisesti eri oppimisksitysten parhaita puolia hydyntvi lhestymistapoja, erilaisia pedagogisia diskursseja. Koulujen kirjallisuudenopetusta suunniteltaessa ja kirjallisuustieteellisi ksitteit opetettaessa on otettava huomioon niin kirjallisuustieteen kuin kasvatustieteen nkkulma. Opetussuunnitelman ja ylioppilaskokeen asettama vaatimus ksitteiden kytst on kohtuuton, mikli ei sovita, miten ksitteet mritelln ja mit ksitteit kokelaiden oletetaan ylioppilaskokeessa hallitsevan. Kirjallisuustieteellisten ksitteiden puutteellisen opetuksen oppikirjoissa ja niiden epmrisen kytn ylioppilaskokeen tehtvnannoissa ja arvioinnissa voi krjistyneimmilln nhd oppilaan oikeusturvakysymyksen
Resumo:
Todays business world demands more and more internal and external integration and transparency among companies at all fields. Integrated ERP (enterprise resource planning) systems offer a possibility to improve business practices and procedures by providing a unified view on the business including all functions and departments. Due to the obvious benefits, the popularity of integrated ERP systems keeps growing. The implementation of ERP systems has however proven risky. The implementation projects tend to be long, extensive, and costly and often they end up in a failure. Due to the significant task and role changes ERP implementation brings to almost everybody in the company, training has been identified as one of the most critical success factors of an ERP implementation. To ensure that the training is conducted in the most effective and successful manner, the training outcomes should be evaluated. So far, training evaluation has however gained only limited attention at most companies investing in different training programs. Uponor corporation has initiated a large ERP implementation and process harmonization program in 2004. Thousands of end-users have been trained during this project so far, and the work still continues until the project is completed in 2010. In this thesis, the evaluation of end-user training in Uponors ERP program is brought further from the current state of performing the basic participant satisfaction survey in the end of each class. The results show that in order to reach reliable training effectiveness evaluation results, not only the reaction towards training but also transfer of skills and attitudes and the final results of the training program should be evaluated.
Resumo:
Analysis of seven pesticides in sediments was successfully achieved using comprehensive two-dimensional gas chromatography with micro-electron capture detection, as it provided higher sensitivity and less matrix interference. Repeatability and intermediate precision of peak areas and heights were less than 4% and the recovery percentage for the analytes ranged from 52 to 115%. Instrumental LOD and LOQ were in the range of 0.60 to 2.31 μg L-1 and 1.83 to 5.62 μg L-1, respectively. Concentrations of 3.34 μg kg-1 (dry basis) for trifloxystrobin and azoxystrobin (below the LOQ) were found in a sediment sample.
Resumo:
Kirjallisuusarvostelu
Resumo:
The growth of biodiesel market and the implementation of regulations related to biodiesel production and biodiesel/diesel blending has encouraged the development of appropriate analytical methods to control the composition of this type of mixture. In this study, an evaluation of the potential of GCGC for the characterization of samples of beef tallow biodiesel and the composition of blends of biodiesel/diesel is presented. The methodology was applied to beef tallow biodiesel and its mixtures with petrodiesel, ranging from B2 to B50. Results allowed not only the identification and quantification of the biodiesel esters, but also the biodiesel percentage in biodiesel/diesel blends.
Resumo:
Kirja-arvio
