Search results for "engineering.material"
showing 10 items of 2352 documents
Spectroscopic analysis used to uncover the original paint colour of the Helsinki Government Palace tower clock faces
2016
The paint stratigraphy of the two clock faces from the tower clock of the Government Palace in Helsinki (Finland) was analysed in order to determine their original colour before restoration works. Paint cross-section samples from both clock faces were analysed by confocal Raman microscopy and scanning electron microscopy coupled to an energy dispersive X-ray spectrometer (SEM-EDS). The results revealed the complex superimposition of paint layers applied over the original black colour. FTIR/ATR analyses proved that the original paint was prepared with linseed oil-resin media. Most likely not all of the different layer colours were visible. Some of the layers were likely to have been a primer…
The use of wood in funerary pyres: random gathering or special selection of species? Case study of three necropolises from Poland
2012
Abstract In this study, the analysis of charcoal remains from three prehistoric necropolises is presented. This botanical material formed part of funerary pyres and thus represents purposely gathered wood used for cremation ceremonies. Therefore, its anthracological analysis may indicate a special selection of wood, which may be a source of palaeoethnographic information about past rituals. However, a question remains as to whether or not the charcoal assemblages that originated from graves may also provide some palaeoecological information. In order to test both hypotheses, analysis of three Polish necropolises dating to the Bronze and the Iron Age were performed. In all charcoal assemblag…
Vegetation changes and human action from the Neolithic to the Bronze Age (7000?4000 B.P.) in Alicante, Spain, based on charcoal analysis
1994
Charcoal analysis reveals various palaeo-ecological phases from the Neolithic to the Bronze Age. Agriculture starts about 7000 B.P. in favourable ecological conditions. Most of the charcoal spectra from sites on the coast represent thermomediterranean holm-oak forest; those from the inland mountains represent mesome-diterranean holm-oak forest. The Neolithic I Impressed Ware people were the first to clear the forest to plant their crops. This clearance of primary woodland resulted in the development of secondary vegetation of pine woods or scrub. The scrub reached its maximum during the Bell Beaker phase and Bronze Age in the Cova de les Cendres. In the Neolithic II open air sites, the perc…
Speciation and oxidation kinetics of arsenic in the thermal springs of Wiesbaden spa, Germany.
2001
Since 1886 arsenic has been known to be present as a trace component in the Wiesbaden thermal waters at concentrations of over 100 microg L(-1). In this study for the first time molecular level speciation of arsenic was measured both in the water (by HG-AAS) and in wellstone scale deposits (by XANES). Most of the arsenic in the anoxic NaCl-type waters is in the reduced arsenite form. Hydrous ferric oxide (HFO) precipitates in the scale deposits scavenge only the minor dissolved arsenate portion which is, however, accumulated up to 3% w/w. Isothermal precipitation experiments at in-situ temperatures showed a difference between the progress of both arsenic and iron oxidation and precipitation…
Mineral control of arsenic content in thermal waters from volcano-hosted hydrothermal systems: Insights from island of Ischia and Phlegrean Fields (C…
2006
This paper documents arsenic concentrations in 157 groundwater samples from the island of Ischia and the Phlegrean Fields, two of the most active volcano-hosted hydrothermal systems from the Campanian Volcanic Province (Southern Italy), in an attempt to identify the environmental conditions and mineral-solution reactions governing arsenic aqueous cycling. On Ischia and in the Phlegrean Fields, groundwaters range in composition from NaCl brines, which we interpret as the surface discharge of deep reservoir fluids, to shallow-depth circulating fluids, the latter ranging from acid-sulphate steam-heated to hypothermal, cold, bicarbonate groundwaters. Arsenic concentrations range from 1.6 to 690…
Development of Eco-Friendly and Self-Cleaning Lime-Pozzolan Plasters for Bio-Construction and Cultural Heritage
2020
Summarization: Nowadays, the design and use of multi-functional mortars has increased significantly, with interesting applications in the green building and cultural heritage conservation sectors. A key point for a correct adoption of these innovative materials is their behavior along time and their resistance to the weathering. The objective of this project was to define the performance and durability of innovative mortars, in order to use them correctly and to avoid irreparable damage over time. For the development of this project, lime–metakaolin and hydraulic lime–metakaolin based mortars (hereinafter called A, B), as well as A and B with the addition of nano-TiO2 and perlite (hereinaft…
Prediction of surface treatment effects on the tribological performance of tool steels using artificial neural networks
2019
The present paper discussed the development of a reliable and robust artificial neural network (ANN) capable of predicting the tribological performance of three highly alloyed tool steel grades. Experimental results were obtained by performing plane-contact sliding tests under non-lubrication conditions on a pin-on-disk tribometer. The specimens were tested both in untreated state with different hardening levels, and after surface treatment of nitrocarburizing. We concluded that wear maps via ANN modeling were a user-friendly approach for the presentation of wear-related information, since they easily permitted the determination of areas under steady-state wear that were appropriate for use…
Growth characteristics of Aspergillus chevalieri and other fungi from under-coating of chocolate truffles
1997
Growth characteristics of fungi, which occasionally affected chocolate truffles, have been studied, using moulded and non-moulded samples. A whitish mycelial growth, located at the filling-coating interface is identified as Eurotium/Aspergillus chevalieri. The spores of other xerophilic molds (Aspergillus fumigatus, A. penicilloides and Penicillium verrucosum) were also found at the filling-coating interface. The water activity of chocolate coating was low enough to prevent fungal growth on the external surface of the truffles. However, the water activity of the filling, due to presence of cream, is sufficient enough to allow the growth of xerophilic moulds. The data on growth characteristi…
Relief and calcium from gypsum as key factors for net inorganic carbon accumulation in soils of a semiarid Mediterranean environment
2021
Abstract In semiarid environments, the total inorganic carbon (TIC) in soil may contribute to the total carbon (C) pool more than the total organic C pool (TOC), thus playing a key role in storing atmospheric CO2. However, due to the different origin pathways of soil carbonates, not all of the TIC pool can be accounted for CO2 sequestration. Indeed, the inorganic C can be accounted for a net sink of CO2 only when calcium (Ca2+) forming carbonates originate from non-carbonate minerals (atmogenic inorganic C, AIC). The aim of this study carried out in a gypsiferous area is to investigate the dissolution of Ca2+ that comes from gypsum (CaSO4·2H2O) in the formation of soil atmogenic carbonates …
Ground-based off-line aerosol measurements at Praia, Cape Verde, during the Saharan Mineral Dust Experiment: microphysical properties and mineralogy
2011
A large field experiment of the Saharan Mineral Dust Experiment (SAMUM) was performed in Praia, Cape Verde, in January and February 2008. This work reports on the aerosol mass concentrations, size distributions and mineralogical composition of the aerosol arriving at Praia. Three dust periods were recorded during the measurements, divided by transitional periods and embedded in maritime-influenced situations. The total suspended particle mass/PM 10 /PM 2.5 were 250/180/74 μg/m 3 on average for the first dust period (17–21 January) and 250/230/83 μg/m 3 for the second (24–26 January). The third period (28 January to 2 February) was the most intensive with 410/340/130 μg/m 3 . Four modes were…