Determinação seletiva de tributilestanho na presença de Sn(IV) em amostras ambientais usando HG-ICP OES e Saccharomyces cerevisiae como material sorvente

A method for selective determination of tributyltin in the presence of Sn(IV) by combining hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP OES) and solid phase extraction (SPE) using baker's yeast is proposed. The procedure is based on selective retention of TBT by the yeast at pH = 6. Detection limit of 1.9 µg L-1 and quantification limit of 6.3 µg L-1 were obtained. TBT and San(IV) were determined in the range of 0-25 µg L-1 and the proposed approach was applied to analyze river water, sea water and biological extracts, with recoveries of 114, 101 and 86%, respectively.

Desidratação de etanol sobre material nanoestruturado do tipo LaSBA-15

La-incorporated SBA-15 mesopourous molecular sieves (LaSBA-15) were directly synthesized with aim to convert ethanol to ethylene. The samples were characterized by XRD, XRF, nitrogen sorption and acidity, by thermodesorption of n-buthylamine. The results have indicated that all the samples have showed high ordered mesostructure with a large average pore size, and that the lanthanum incorporation has caused an increase in the acidity of the SBA-15. The LaSBA-15 samples have improved, with low deactivation rate, the conversion of the ethanol to water, ether, acetaldehyde and ethylene. In addition, they have increased the ethylene selectivity.

Eletrodos positivos tubulares para baterias chumbo ácidas produzidas com material ativo nanométrico

Conventional stationary lead acid batteries positive tubular plates have a specific capacity of about 120 Ah/kg. This value represents an active material utilization coefficient of 50%. The production of these plates includes some initial processes to generate the active PbO2 from a precursor material. In the present work it will be presented a proper and novel methodology to assemble tubular plates directely with nanometric powder of PbO2 particles. The utilization coefficient of these plates was about 80%, and they were able to endure more than 130 severe duty cycles. This high utilization coefficient is a higly desirable feature for electric vehicles batteries.

Conversioni al cattolicesimo a Roma tra Sei e Settecento. La presenza degli scandinavi nell’Ospizio dei Convertendi.

In my PhD dissertation, I have examined a group of people of Scandinavian origin received by Ospizio dei Convertendi. This group has been hitherto largely unknown to historical research. The Ospizio was an institute founded by the Oratorian Congregation in Rome in 1673 to provide religious instruction and material aid to both recent and aspirant converts to Roman Catholicism. My research traces the profile of converts and a typology of motives, examining different factors which influenced the conversion process. I show that the key factors were often of a social rather than a religious nature. Moreover, I have analyzed the hospice in the context of Counter-Reformation charity as well. In terms of numbers, the Scandinavians formed a somewhat marginal yet not insignificant group within the Roman hospice. Out of a total of 2203 guests received between 1673 and 1706, 4.6 % were Scandinavians: 74 Swedes (including Finland and Livonia) and 27 Danes (including Norway). They came from a rigorously Protestant region which reacted to Catholicism with severe legislative measures. Converts to Catholicism risked confiscation of their goods, expulsion or even capital punishment. Since both Sweden and Denmark were practically impenetrable to Catholicism at the time and clandestine missionary attempts often failed before they had even properly started, the Roman Catholic Church shifted its interest towards Northerners arriving in Rome, a preferred destination for young noblemen, artists and migrant craftsmen. The material related to Ospizio dei Convertendi, conserved in the Vatican archives, is a scarcely known yet unusually rich source, not only for the religious history of our continent, but also for social history and the study of migration in early modern Europe. It contains a wealth of information about members of the subordinate classes, of their travels and lives in Europe. The profile delineated in these documents is of individuals who had a wide range of different professions and different aspirations. These documents encompass a vast social spectrum that was highly mobile on a continent which by that time had become pluriconfessional. Therefore, these migrants faced the complex religious reality in their everyday life. The principal corpus of my research consists of two types of manuscript sources created for administrative and in a way also for apologetic purposes of the Roman Catholic Church. My starting point is the Primo registro generale of Ospizio dei Convertendi. This is a volume in which the following information about each guest was registered: name, nationality, city of origin, age, sex, profession, confession professed before converting, date of arrival, departure, abjuration and baptism. Typically, the convert was male, originating from Stockholm or Copenhagen, from 21 to 30 years of age. The biggest occupational groups in descending order were soldiers, noblemen, craftsmen and sailors. Thus the data reflects a multiform reality of interurban and long distance migration, ideals regarding the education of young noblemen and gentry as well as the need of European armies to hire foreign mercenaries in their various campaigns. Against this background the almost total absence of women is hardly surprising: there is only one woman in the material I have studied. The second main source, Nota degl’ospiti ricevuti e spese fatte per essi, sheds more light on the choices of the converts, their motivations and their lives outside Scandinavia before reaching Rome. This narrative material permits an analysis which completes but also goes far beyond the columns of the Institute’s general register. This material consists of reports written by Catholic priests based on an interview conducted upon each guest’s arrival. The material frequently includes information on what the converts would do following their departure from the Institute as well. These sources have a specific narrative form and contain short biographies, list reasons for converting and information about the journey from the North to the Mediterranean - a journey which in many cases took several years. Moreover, they show that certain unorthodox practices such as calling on the saints and pleading for help from them were not uncommon in the Protestant popular religion. The recording of information on conversions from Protestantism to Catholicism reflects both religious and social interest on the part of the receiving institute. The information obtained was used for the purposes of religious teaching, for finding adequate ways of inserting the convert into Italian society so that he could earn a living, and to find effective methods to convert others with a similar cultural and geographical background. The stories recorded were based on interviews with the newly-arrived, information obtained from a travel companion or fellow countrymen, or from written documents the aspirant converts carried with them. These sources illustrate, although sometimes in rather simplified ways, the circumstances and motivations which were relevant to the choice of changing one’s confession. In addition, I have examined petitions addressed to the hospice and other Roman authorities in order to get financial aid. These petitions were written by Italian scrittori, and they contain certain conventions and topoi of presenting the conversion with the purpose of improving the chances of obtaining financial aid. It is through these filters, which may seem initially almost invisible, that the remote voice of the converts reaches us. The results of the analysis are particularly interesting because they disagree with some of the principal conclusions of previous work on the subject. First, earlier research has focused almost exclusively on the conversions of noblemen, and has argued, second, that the Queen Christina of Sweden was the driving force behind their change of confession. The sources examined for this dissertation present a profile of long-distance migrants, many of them members of the subordinate classes, who were looking for ways to make their living in Europe. These people had in many cases left their country of origin several years earlier and not for religious reasons, so, crucially, we are not dealing with confessional migration in these cases. Rather, conversion was a complex process, intricately tied up with strategies of survival, integration and upward social mobility. At the same time, while these components are significant on their own right, they do not necessarily point to the absence of motivations of a more clearly religious nature.

Remoção dos hormônios 17β-estradiol e 17α-etinilestradiol de soluções aquosas empregando turfa decomposta como material adsorvente

This paper describes the adsorption of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solution by decomposed peat. The peat presented a good adsorption process, close to 76.2% for E2 removal and approximately 55.0% for EE2. Moreover, the results indicated a probable multi-layered process. Adsorption isotherms were well fitted by Freundlich model. The data were evaluated considering the pseudo-first-order and pseudo-second-order approaches, being the second more significant mechanism in the rate-controlling step. Thermodynamic data revealed that hormones adsorption onto peat is spontaneous under the employed experimental conditions. The results confirmed the potential of this adsorbent to be employed for effluents treatment.

Strategic practices : : hidden histories of gender in Finland 1880-2005 : projektikuvaus

Ajankohtaista

A quantitative validated method using liquid chromatography and chemometric analysis for evaluation of raw material oF Maytenus ilicifolia (Schrad.) Planch., Celastraceae

The hydroalcoholic extracts prepared from standard leaves of Maytenus ilicifolia and commercial samples of espinheira-santa were evaluated qualitatively (fingerprinting) and quantitatively. In this paper, fingerprinting chromatogram coupled with Principal Component Analysis (PCA) is described for the metabolomic analysis of standard and commercial espinheira-santa samples. The epicatechin standard was used as an external standard for the development and validation of a quantitative method for the analysis in herbal medicines using a photo diode array detector. This method has been applied for quantification of epicatechin in commercialized herbal medicines sold as espinheira-santa in Brazil and in the standard sample of M. ilicifolia.

A retórica da linguagem científica: das bases teóricas à elaboração de material didático para o ensino superior de Química

This work is part of a study that focused on analyzing the contributions of didactic activities related to scientific language rhetoric characteristics aimed at developing students' abilities to identify such characteristics in chemistry scientific texts and critical reading of those texts. In this study, we present the theoretical basis adopted to determine the scientific discourse characteristics and for the production of the didactic material used in those activities. Latour, Coracini and Campanario studies on persuasive rhetorical strategies present in scientific articles aided the production of such material.

Certified reference material to water content determination in bioethanol fuel

Bioethanol is a strategic biofuel in Brazil. Thus, a strong metrological basis for its measurements is required to ensure the quality and promote its exportation. Recently, Inmetro certified a reference material for water content in bioethanol. This paper presents the results of these studies. The characterization, homogeneity, short-term stability and long-term stability uncertainty contributions values were 0.00500, 0.0166, 0.0355 and 0.0391 mg g-1, respectively. The certificated value for water content of bioethanol fuel was (3.65 ± 0.11) mg g-1. This CRM is the first and up to now the unique in the world.

Elementos traço em material particulado atmosférico de uma região agroindustrial do sudeste do Brasil

Trace element concentrations were measured in atmospheric particulate matter collected in 2009 and 2010, in a Brazilian region influenced by pre-harvest burning of sugar cane crops. For coarse particles, high concentrations of Al, Fe, K and Ca suggested that re-suspended soil dust was the main source of aerosol trace elements, subsequently confirmed by XRD analysis. High levels of K, Zn, As, Cd and Pb were found in fine particles, confirming the contribution of biomass burning and vehicle emissions, whereas Na, Al, K, Fe and Zn were the representative elements in ultrafine particles, influenced by a diversity of sources.

Caracterização detalhada de material de referência certificado de carvão brasileiro

The use and characterization of the first Certified Reference Material (CRM) of Brazilian coal for analytical quality control are presented. All results were determined within the limits of repeatability and reproducibility allowed under the standards. Notable among the characterization parameters was the mineral matter content (45.39%) obtained by an alternative procedure showing a low relative error (-2.1%) compared to the standard technique (low ashing temperature). The possible expanded application of this CRM application in national laboratories, beyond the certificated and reference parameters, has advantages such as lower cost and easy availability, but round robin tests must be performed.

Análise exploratória rápida e não destrutiva (screening) da presença de elementos químicos tóxicos em material escolar por fluorescência de raios x

Compulsory in Brazil, toy certification aims to prevent possible risks in toy use. The Brazilian National Institute of Metrology (INMETRO) establishes the maximum concentration of toxic elements (TE) that may be present in toys. This study evaluates the presence of TE in different crayons, gouache and modeling clays using X-ray fluorescence. This technique is fast, has low operating cost and minimum sample pretreatment, resulting in a clean procedure without reagent consumption and waste generation. Bromine (in gouache) and Barium (in crayons) were the only potentially TE identified in the samples studied.

Síntesis química, estudios de caracterización y reactividad de un material catalítico a base de ZrO2-H3PW12O40

In this work, the preparation and characterization of materials such as zirconium oxide (ZrO2) and phosphotungstic acid promoted zirconium oxide (ZrO2-H3PW12O40) is presented. Physico-chemical characterization results showed that addition of H3PW12O40 acted as both a textural and chemical promoter of zirconium oxide. The incorporation of phosphotungstic acid into the ZrO2 matrix delayed the sintering of the material and stabilized ZrO2 in the tetragonal phase. ZrO2 acidity was also enhanced, developing strong acid sites on its surface. The Pt/ZrO2-H3PW12O40 catalyst was active for n-pentane isomerization at 250 °C, exhibiting high selectivity to iso-pentane (95%). This result is probably due to its suitable acidity.

Síntese do material mesoporoso MCM-41 usando esponja de água-doce como fonte de sílica

Fresh water sponge was used as a silica source for the synthesis of MCM-41 via the hydrothermal process. The silica was extracted from the sponge by washing with nitric acid and piranha solution. Synthesis of MCM-41 was performed at 100 °C for 5 days and the procedure was optimized, with modifications made to the leaching temperature of the silica and the synthesis of mesoporous material, which was characterized by XRD, FT-IR, SEM and adsorption of N2. The optimal result was achieved at a temperature of 135 °C for 3 days, showing ordered mesoporous material with a surface area of 1080 m² g-1.

Bateria de métricas para avaliação da verdura material de reações de síntese

The use of a battery of three mass metrics (atomic economy - AE, reaction mass efficiency - RME, and mass intensity - MI) for systemic evaluation of the material greenness of synthesis reactions is presented. Material greenness is discussed in terms of materialization/dematerialization of the reaction system and also according to the first two Principles of Green Chemistry, and is shown to involve two components: atomic greenness (incorporation of the atoms provided by reagents into the product, evaluated by AE and RME); and massic greenness (global mass of reagents and non-stoichiometric materials, evaluated by MI, related to the production of residues).