Characterization of archaeological bronze corrosion products crossing EIS with voltammetry of immobilized particles

Electrochemical impedance measurements were applied to microparticulate deposits of copper corrosion products attached to graphite electrodes in contact with different aqueous electrolytes (0.25 M HAc/NaAc (pH 4.75), 0.10 M HCl and 0.10 M HClO4) and the application of an interval of potentials between +0.25V to -0.75V. The conditions of operation were selected from a compromise between repeatability and sensitivity, being 0.10 M HClO4 and bias potential of 0.25 V adopted. The electrochemical impedance data were modeled on the basis of available equivalent circuits for corroded metal surfaces and the correlation between several pairs of circuit elements provided the characterization of different corrosion compounds regardless the amount of microparticulate solid on the electrode. Electrochemical grouping of samples from the archaeological Roman site of Gadara (Jordan, 4th century AD) suggests different provenances/manufacturing techniques, consistent with voltammetry of immobilized particles (VIMP) measurements. Thus, illustrating the capabilities of the intersection of such techniques in the archaeometric domain

Monitoring Corrosion Products on Metal Artefacts by Linear Sweep Voltammetry (LSV)

Metallic surfaces are highly sensitive to their surroundings, and prone to react with airborne pollutants to form complex layers. Electrochemical techniques have the possibility of simultaneously identifying different electroactive compounds [1]. The high sensitivity of Linear Sweep Voltammetry (LSV) allows the detection of extremely thin surface films before they became visible. LSV leads to reduction peaks, which can identify the compounds within the “tarnishing” layer and also its relative abundance [1, 2]. The potentialities of this and others electrochemical techniques has been well demonstrated in several recent works and they seem to be promising and non-invasive tools, even for in situ investigations on the metallic artifacts from cultural heritage. This communication presents data showing the application of the technique to silver and sterling silver coupons exposed, during periods of 1 and 12 months, in the Treasure Room in the Museum (inside showcases) and near the Holy Altar of the Chapel, of Porto Cathedral (Portugal). The influence of various conditions: the atmosphere (Museum and Chapel), exposure time (1 and 12 months) and season (spring, summer, autumn and winter) have been analysed. The LSV spectra of blank polished samples as well as samples covered with thin films of silver sulphide and of silver chloride, formed under controlled conditions, respectively: (i) H2S, 1000 ppm, RH= 53% ± 2, T= 21 ºC ± 1, over periods of 24, 48 and 72 h) and (ii) 3.5% of NaCl, RH=41% periods of 5 h, have been used as references. Concerning the nature of the products developed on the surface during the exposure, data has revealed that the tarnishing layers have a complex nature and are not composed only by silver sulphide. It happens even that silver sulphide is a relative minor component in the tarnish layer. Peaks corresponding to silver chloride and silver oxides were well visible. Small peaks assigned to silver sulphide were identified on the samples exposed in the Chapel. For the 12 months exposures both peaks have increased in size with the peak assigned to chloride being much higher in the case of the Chapel. The seasonal influence, even for the 1 month exposures, was particularly notable on those samples with exposures started in winter with well visible effects on the chloride peak on the tarnish layer of the samples exposed in the Chapel. Obviously, that to obtain analytical information electrochemical techniques can be complemented with spectroscopic techniques, namely, X- ray photon spectroscopy (XPS), laser induced breakdown spectroscopy (LIBS), x-rays fluorescence spectroscopy, among others. [1] A. Doménech-Carbó, M.T. Doménech-Carbó, V. Costa (2009), Electrochemical Methods in Archaeometry, Conservation and Restoration, Berlin: F. Scholz. [2] V. Costa, M. Dubus (2007), Impact of the environmental conditions on the conservation of metal artifacts: an evaluation using electrochemical techniques, in National Museum of Denmark, Museum Microclimates, Copenhagen: T. Padfield and K. Borchersen, 63-65

Testing a Flux Cell for Determination of Manganese in Freshwater

A flux cell with vitreous carbon tubular electrodes, as auxiliary and working electrodes, was tested. The following procedure was used: (1) study and optimization of the mercury deposition conditions at the working electrode, (2) study the electrodes position and distance in order to minimize dispersion of the sample, (3) study of the linearity and reproducibility using different concentrations of manganese (2.10-7 to 6.10- 7 M), with differential pulse anodic stripping voltammetry (DPASV) and square wave stripping voltammetry (SWSV). Good linear correlation was obtained for concentration of manganese used.This work is within the context of Research Project F.C.T.-PRAXIS/C/qui/ 10035/1998

In situ continuous monitoring of chloride, nitrate and ammonium in a temporary stream. Comparison with standard methods.

A multi-parameter probe was used for in situ chloride, nitrate and ammonium measurements in a temporary stream (Ribeira da Pardiela, in the South of Portugal). Comparison with standard analytical methods was performed for all elements. For chloride, the results of the probe depicted the same behaviour as that obtained with the standard method, although it is clear that the matrix effects were present. For nitrate, the results obtained with the probe were in agreement with the other standard methods used, except for samples collected during drought, when the stream water became brownish and exhaled an offensive smell, due to the decomposition of organic matter. For ammonium, surprisingly the probe show to be the best option, the phenate method being affected by matrix effects. The results still suggest an interference of the bicarbonate ion on nitrate determination, but standard additions approach was shown to minimize most of the matrix effects. Recoveries were reasonable to good for all the three anions under scrutiny

Voltammetric Behaviour of Cu-NTA and Pb-NTA on a Mercury Iridiun Microelectrode Coated with Agarose

The complexation of nitriloacetic acid (NTA) with copper and lead was studied by square wave stripping voltammetry (SWSV) using a mercury iridium microelectrode as the working electrode. The results show that NTA interfere with the measurements, but if the mercury iridium microelectrode is coated with different concentrations of agarose (0.75%, 1.5% and 15% w/v) this interference is greatly minimized. The best results were obtained with 1.5% agarose.This work is within the context of Research Project F.C.T.-Sapiens/POCTI 32616/Qui/2000

Caracterización del perfil de lenguaje en el trastorno depresivo y el dolor crónico

[ES] La depresión es un trastorno significativo, que afecta a más de 300 millones de personas en el mundo. Se la considera “el resfriado común” de los trastornos mentales. Esta enfermedad provoca alteraciones en el humor, la cognición y el lenguaje y, a menudo, se instala en comorbilidad con otros cuadros clínicos, como el dolor crónico. En cuanto a su diagnóstico, habitualmente se basa en criterios clínicos, sacados de la entrevista y de la búsqueda de síntomas. Todavía, no siempre los deprimidos saben que lo están, y tampoco logran transmitirlo. Buscan comprensión, pero no son comprensibles. Buscan que alguien los escuche, pero no son audibles. Se expresan con el caminar, con la mirada, con la expresión facial y por supuesto, con el lenguaje. Así, el lenguaje, en sus múltiples dimensiones, podría actuar como herramienta auxiliar de diagnóstico y de planificación psicoterapéutica. Si bien el cuerpo teórico de la literatura está aumentando, los estudios sobre las características del lenguaje en la depresión y en el dolor crónico siguen siendo un desafío. El objetivo de la presente investigación es aportar datos válidos sobre los indicadores lingüísticos presentes en la narrativa de personas con trastorno depresivo y con dolor crónico, comparativamente a controles saludables, utilizando las narrativas de experiencias personales significativas en cuanto método de obtención de corpus textuales, cuyo análisis permite reconstruir la estructura del lenguaje corriente, utilizado naturalmente, de forma particularmente inequívoca y de fácil obtención. Nuestro estudio utilizó un enfoque de análisis del contenido, con recurso a LIWC®, y de la prosodia, con recurso a Praat®, para calificar la muestra de lenguaje recopilada. Los resultados confirman la existencia de indicadores lingüísticos para las personas deprimidas: la mayor utilización de pronombres, principalmente de pronombres de primera persona del singular, de palabras sociales y de palabras relacionadas con la percepción, menos palabras relacionadas con emociones positivas, menos adverbios, menos cuantificadores y menos palabras relativas a la relatividad y el tiempo. Respecto a la prosodia, utilizan más pausas, pausas con mayor duración, mayor proporción de pausas y menor proporción de fonación y además, presentan una menor dinámica de la prosodia. En cuanto a la narrativa de personas con dolor crónico, se caracteriza por la mayor utilización de palabras relacionadas con emociones negativas y un menor uso de palabras relativas a los procesos cognitivos. Estos datos se suman a la convincente variedad de literatura sobre la estrecha relación entre el lenguaje y la salud y proporcionan evidencias de que las características lingüísticas son indicadores sensibles y específicos del estado emocional, psicológico y físico del narrador, por lo que tienen utilidad diagnóstica, o más específicamente, implicaciones en la precisión diagnóstica y en la adecuación de las intervenciones

O Monte Alentejano na encruzilhada do tempo

O tradicional monte alentejano é um tipo de habitat constituído, pelo menos até finais dos anos 70, por estruturas arquitectónicas detentoras, em muitos casos, de um património vernácula inigualável. Nos últimos 30-40 anos assistiu-se a uma dinâmica sócio-económica que, se por um lado levou a uma maior racionalização dos sistemas agrícolas, com a intensificação da mecanização, desenvolvimento das monoculturas, introdução de novas culturas, etc., foi, por outro lado, acompanhada por um despovoamento rural crescente e pela alteração radical das redes sociais locais, com a evidente quebra da coesão social, entre outros problemas. Mas o que terá acontecido durante este período ao monte alentejano? Qual foi a trajectória de conversão para as novas funcionalidades? Estará o monte alentejano condenado a desaparecer ou a diluir-se noutra realidade? O que aconteceu aos seus valores patrimoniais? Os autores pensando que esta problemática não tem sido encarada pelos órgãos políticos responsáveis com a devida competência, nem merecendo da sociedade a devida atenção, propõem-se realizar um estudo comparativo de situações actuais, correspondentes a zonas geográficas e a tipos de uso do solo distintos, no Alentejo Central. Esta comparação será tanto mais enriquecedora quanto mais distintas forem as paisagens, pois só assim se perceberá se o problema atinge indiferenciadamente todo o território, ou se, pelo contrário, assume maior gravidade em algumas paisagens particulares. Afinal, o risco, é que, com a necessidade de se produzir para um mercado global, acarretando a descaracterização de muitos sistemas agrícolas tradicionais, paisagens de elevado valor patrimonial, como o montado, a par de um património vernacular por vezes rico, fiquem cada vez mais expostas e degradadas. Pretende-se, a partir deste olhar, tentar perceber os diferentes caminhos que têm conduzido o monte alentejano a alterações nem sempre evidentes e percepcionáveis.UID/HIS/00057/2013 (POCI-01-0145-FEDER-007702

Is social coesion affecting heritage landscape perservation and interpretation?

Usually heritage landscape is seen as a natural and a cultural resource. But, in the base of those landscapes we can meet social practices, an intangible heritage that give cohesion to the natural and cultural aspects. Our scope it's to debate ideas comparing examples. Between the well preserved Chinese rice heritage landscapes, supported by millenary social and farming practices, and the abandoned European terraces, an essential social question emerges: the preservation of the landscape heritage is supported not only by natural and cultural elements but also by social practices, technical knowledge and ways of understanding Nature. Efforts to the heritage landscape maintenance has been limited to the natural and cultural elements preservation, forgetting often the referred social cohesion factors. To safeguard heritage, the cultural landscape should be duly interpreted which means the understanding of the ecological, social and even economic functionality of the landscape structures.UID/HIS/00057/2013 (POCI-01-0145-FEDER-007702

GESTÃO DE RESÍDUOS NOS LABORATÓRIOS DA UNIVERSIDADE DE ÉVORA (2007-2021)

WASTE MANAGEMENT IN THE LABORATORIES OF THE UNIVERSITY OF ÉVORA (2007-2021). Waste generated in university laboratories is an important component of university waste management, especially regarding their hazardousness and, also, the cost involved in their forwarding. To make a good management of this waste, it is essential to know the amount generated and the composition. However, this type of information remains scarce. In this work, waste from the laboratories of the University of Évora (Portugal) was surveyed from 2007 to 2021, using existing records. In the 15 years under analysis, the laboratories of the University of Évora generated about 61 tonnes of waste, 88% of which were hazardous and 66% were in the liquid state. In addition, only 3% of this waste was subjected to recovery operations. Moreover, the COVID-19 pandemic contributed to a double increase in hospital waste generated and to a substantially decreased of hazardous liquid waste from the laboratory activity, especially in the first year of the pandemic. In 2021, the second year of the pandemic, there was a “return to normality”, reaching the highest value of waste generated in the laboratories, of 8.6 tonnes. Finally, possible solutions for improving laboratory waste management were also discussed

Controlling pollution effects on metallic cultural heritage using linear sweep voltammetry

This work demonstrates the potentialities of the linear sweep voltammetry (LSV) for monitoring the composition of the tarnishing layers formed on silver and on the silver-copper alloys exposed to atmospheres contaminated with pollutants, such as H2S and chloride ions, among others. A collection of silver and sterling silver coupons exposed during periods of 1 and 12 months, at the Holy Altar of the Chapel and at the Treasure Room of the Museum, both of the Porto Cathedral (Portugal), with exposures started in march 2010 and ending in march 2011, have been analysed by LSV. The LSV spectra of blank polished samples as well as samples covered with thin films of silver sulphide and of silver chloride, formed under controlled conditions, respectively: (i) H2S, 1000 ppm, RH= 53% ± 2, T= 21˚C ± 1, over periods of 24, 48 and 72 h and (ii) 3.5% of NaCl, RH=41%, T= 43˚C, periods of 5 h, have been used as references. The influence of the atmosphere (Chapel and Museum), exposure time (1 and 12 months) and season, in which the exposures were started, (spring, summer, autumn and winter) have been analysed on the LSVs of the coupons exposed to the various conditions. For the 1 month exposures started in spring the peaks corresponding to the silver sulphide and silver chloride were, as expected, higher on the samples exposed in the Chapel. For the 12 months exposures both peaks have increased in size with the peak assigned to chloride being much higher in the case of the Chapel and the reverse observed in the case of the Museum. The seasonal influence, even for the 1 month exposures was particularly notable on those started in winter with well visible effects on the sulphide and chloride peaks respectively, in the Museum and Chapel exposures