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

"Uma casa portuguesa, com certeza" : design de interiores para os aviões da companhia aérea de Portugal (1945-1979)

O contexto no qual se insere o presente artigo deriva de uma investigação para doutoramento em design (FAUL) nas áreas da História e Critica de design sobre a companhia aérea TAP Portugal, desde a sua génese (1945) até ao ano em que alterou a designação para Air Portugal (1979). O espaço interior de um avião de uma companhia de bandeira foi sempre uma extensão territorial “encenada” para consumo interno e externo, o que justificou, no caso dos TAP, um compromisso entre a ideologia e o gosto oficial do Estado Novo e os clichés da indústria de turismo à escala internacional. “Portugal no ar”, metonímia de avião TAP, procurou transmitir a imagem de um país moderno (apenas existente “nas nuvens”). Apesar da crescente importância da tecnologia, em linha com os êxitos da engenharia aeronáutica, cada avião TAP conseguiu ser a “casa portuguesa”, onde nacionais e estrangeiros puderam antecipar a chegada a Portugal, ou guardar a última recordação do país.Abstract : The context in which this article is presented derives from a Phd research in design (FAUL) covering the areas of Design History and Criticism on the airline TAP Portugal, since its beginnings (1945) until the year in which the designation changed to Air Portugal (1979). The interior of a flag carrier aircraft was always a territorial extension “staged” for inner and outer consumption, which in TAP’s case meant, a compromise between the ideology and the official taste of the Estado Novo, and the international tourism clichés. "Portugal in the air," metonymy for a TAP airplane, sought to express the image of a modern country (only existing "in the clouds"). Despite the importance of technology, achieved by the successes of aeronautical engineering,info:eu-repo/semantics/publishedVersio

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

The chaperone balance hypothesis: The importance of the extracellular to intracellular HSP70 ratio to inflammation-driven type 2 diabetes, the effect of exercise, and the implications for clinical management

Recent evidence shows divergence between the concentrations of extracellular 70 kDa heat shock protein [eHSP70] and its intracellular concentrations [iHSP70] in people with type 2 diabetes (T2DM). A vital aspect regarding HSP70 physiology is its versatility to induce antagonistic actions, depending on the location of the protein. For example, iHSP70 exerts a powerful anti-inflammatory effect, while eHSP70 activates proinflammatory pathways. Increased eHSP70 is associated with inflammatory and oxidative stress conditions, whereas decreased iHSP70 levels are related to insulin resistance in skeletal muscle. Serum eHSP70 concentrations are positively correlated with markers of inflammation, such as C-reactive protein, monocyte count, and TNF-a, while strategies to enhance iHSP70 (e.g., heat treatment, chemical HSP70 inducers or coinducers, and physical exercise) are capable of reducing the inflammatory profile and the insulin resistance state. Here, we present recent findings suggesting that imbalances in the HSP70 status, described by the [eHSP70]/[iHSP70] ratio, may be determinant to trigger a chronic proinflammatory state that leads to insulin resistance and T2DM development. This led us to hypothesize that changes in this ratio value could be used as a biomarker for the management of the inflammatory response in insulin resistance and diabetes

A connected and automated vehicle readiness framework to support road authorities for C-ITS services

Connected and Automated Vehicles (CAVs) can have a profound influence on transport systems. However, most levels of automation and connectivity require support from the road infrastructure. Additional support such as Cooperative Intelligent Transport Systems (C-ITS) services can facilitate safe and efficient traffic, and alleviate the environmental impacts of road surface vehicles. However, due to the rapidly evolving technology, C-ITS service deployment requirements are not always clear. Furthermore, the costs and benefits of infrastructure investments are subject to tremendous uncertainty. This study articulates the requirements using a structured approach to propose a CAV-Readiness Framework (CRF). The main purpose of the CRF is allowing road authorities to assess their physical and digital infrastructure readiness, define requirements for C-ITS services, and identify future development paths to reach higher levels of readiness to support CAVs by enabling C-ITS services. The CRF is intended to guide and support road authorities' investment decisions on infrastructure

Legume and Nitrogen Fertilization Affect Animal Performance and Enteric Methane Emission of Nellore Heifers

Methane emission from livestock operation is an important source of greenhouse gas and contributes to global warming. Forage legume secondary compounds may mitigate methane emissions by reducing methanogenic population in the rumen. This study evaluated animal performance and methane emission from beef cattle grazing either a mixed pasture [Brachiaria brizantha cv. Marandu (palisadegrass) and Arachis pintoi (forage peanut) cv. BRS Mandobi] or a palisadegrass monoculture with or without nitrogen (N) fertilisation. A 2.5-yr continuous stocking experiment was carried out in southeast Brazil, on a randomized complete block design with three treatments and four replicates. Two Nellore heifers were used as tester animals and additional put-and-takes were used to keep canopy height at 20-25 cm. The treatments comprised three pasture types: 1) palisadegrass-forage peanut mixed pasture (GRASS+LEGUME); 2) palisadegrass + 150 kg N/ha/year (GRASS+N); 3) palisadegrass without N fertilization (GRASS). Response variables included average daily gain (ADG), forage intake, and methane emission. Methane emission was estimated by the sulphur hexafluoride (SF6) tracer technique. There was no difference between grazing systems for the ADG (P = 0.439) and DMI (P = 0.394; averages of 0.433 kg/d and 2.10 %BW/d, respectively). In the GRASS+LEGUME, there was a decrease of 11.7% in methane emission per animal (148 vs. 170 and 165 g/day for GRASS+N and GRASS, respectively; P = 0.001). Grazing systems including legume reduced methane emission per unit of ADG (365 vs. 428 and 398 g/kg for GRASS and GRASS+N, respectively; P = 0.061) and per carcass gain (656 vs. 800 g of methane/kg carcass for GRASS; P = 0.022). Intake of condensed tannins was greater for GRASS+LEGUME (0.61 vs. 0.17 %BW/d, P \u3c 0.001). Forage peanut decreased enteric methane emission intensity, reducing carbon footprint of livestock systems in Southeast Brazil

How Does N Fertilization or Forage Legumes Affect Forage and Animal Production?

Livestock grazing in tropical climates is characterized by low productivity. Forage and animal production can be improved by applying nitrogen (N) fertiliser or using forage legumes. This 2.5-yr study assessed the canopy structure and productivity of beef cattle grazing either a mixed pasture of Brachiaria brizantha cv. Marandu (palisadegrass) and Arachis pintoi (forage peanut) cv. BRS Mandobi or a Marandu palisade grass monoculture with or without N fertilisation. The experiment was carried out in Southeast Brazil, where the canopy structure (herbage mass) and animal productivity (stocking rate and liveweight gain per ha) were compared for three types of pastures: 1) mixed pasture of Marandu palisade grass and forage peanut (GRASS+LEGUME); 2) a monoculture of Marandu palisadegrass fertilised with 150 kg N/ha/year (GRASS+N); and 3) monoculture of Marandu palisadegrass without N application (GRASS), under continuous stocking. A minimum of two Nellore heifers and additional put-and-takes were used to keep canopy height at 20-25 cm. A randomized complete block design was used with four replicates; seasons were considered repeated measurements over time. Herbage mass was greater in the GRASS+N pasture (P \u3c 0.001); however, in the last three seasons (Spring II, Summer III, and Fall III), there was no difference to GRASS+LEGUME pasture. In the GRASS+LEGUME pasture, there was an increase of legume mass (1.260 to 2.565 kg/ha) and botanical composition (23.6 to 39.1% of legume in forage mass) throughout the study. The stocking rate (P \u3c 0.001) and liveweight gain per ha (P \u3c 0.001) were greater in GRASS+N, without difference among GRASS+LEGUME and GRASS pastures in the first seven seasons. In the last three seasons, with an increase of legume proportion, stocking rate and liveweight were intermediate for GRASS+LEGUME pasture. Legume increased herbage mass and animal productivity in the long term. Immediate responses were achieved with N fertilization

Anharmonic transitions in nearly dry L-cysteine I

Two special dynamical transitions of universal character have been recently observed in macromolecules at $T_{D}\sim 180 - 220$ K and $T^{*}\sim 100$ K. Despite their relevance, a complete understanding of the nature of these transitions and their consequences for the bio-activity of the macromolecule is still lacking. Our results and analysis concerning the temperature dependence of structural, vibrational and thermodynamical properties of the orthorhombic polymorph of the amino acid L-cysteine (at a hydration level of 3.5%) indicated that the two referred temperatures define the triggering of very simple and specific events that govern all the biochemical interactions of the biomolecule: activation of rigid rotors ($T<T^{*}$), phonon-phonon interactions with phonons of water dimer ($T^{*}<T<T_{D}$), and water rotational barriers surpassing ($T>T_{D}$).Comment: 4 pages, 4 figures, submitted to Physical Review Letter