Search results for "Charcoal"
showing 10 items of 102 documents
Effect of Heating Time and Temperature on the Chemical Characteristics of Biochar from Poultry Manure
2014
Poultry manure (PM) chars were obtained at different temperatures and charring times. Chemical-physical characterization of the different PM chars was conducted by cross-polarization magic angle spinning (CPMAS) (13)C NMR spectroscopy and thermal analysis. CPMAS (13)C NMR spectra showed that the chemical composition of PM char is dependent on production temperature rather than on production duration. Aromatic and alkyl domains in the PM chars obtained at the lowest temperatures remained unchanged at all heating times applied for their production. The PM char obtained at the highest temperature consisted only of aromatic structures having chemical nature that also appeared invariant with hea…
A view of the vegetation and economic exploitation of the forest in the Late Neolithic sites of Les Jovades and Niuet (Alicante, Spain)
1992
SummaryThe results of the charcoal analysis obtained in two open air sites of the Late Neolithic, although contrasting with what is known so far about their economy, as well as with the results of different palaeoamblental studies undertaken in other sites, mainly caves with long sequences, within the same area or in other near areas, form the main interest of this paper. We will begin presenting the data pertaining to both sites individually which, in the final part, will be assessed in order to reach a better understanding of the relationship between men and their natural environment during the Neolithic period.
Mid-Holocene forests from Eastern Hungary: New anthracological data
2013
Charcoal remains found in five archaeological sites provided an important source of information about the woody vegetation that developed during the Atlantic period in eastern Hungary. The results are presented jointly since all sites are located in very similar habitats, they reflect Neolithic cultures and present comparable floral compositions. The reconstruction of past forest communities from the Great Hungarian Plain in the Atlantic period is based on pollen analysis and new anthracological data offer significant complementary information to the established pollen sequences. These data were obtained from more than 5000 charcoal fragments in which 28 taxa were identified. The main contr…
An anthracological approach to understanding Late Classic period cultural collapse in Mesoamerica’s northwestern frontier
2012
International audience; For over 50 years, researchers have suggested that increased regional rainfall over the highland deserts of Mesoamerica's northwestern frontier zone during the Classic period (AD 200-900) allowed for the colonization of the zone by farming groups who originated from Central and/or West Mexico. A severe and prolonged drought is hypothesized to have later provoked the abandonment of the region by these sedentary populations by AD 900. However, very little research has been carried out in the zone to detect evidence of this proposed climate change. I present results from the first systematic study of wood charcoal from the northwestern frontier, comparing the data from …
Micro-scale post-fire surface cover changes monitored using high spatial resolution photography in a semiarid environment: A useful tool in the study…
2012
[ES] Although post-fire soil erosion has been studied, little attention has been paid to changes in soil surface cover following fires, despite this being a key factor in understanding the water and sediment yield. This study, at Peñaflor (Spain), investigated the effect of fire on soil erosion using data from soil erosion plots and high spatial resolution photography (HSRP). Measurements were made from October 2003 to October 2005 in a control plot and a plot experimentally exposed to a fire in October 2004. Ground cover components were identified, including vegetation, bare soil, stones, charcoal and ash. Runoff and sediment concentrations were low because of the absence of intense rainfa…
Successful treatment of paraquat poisoning: activated charcoal per os and "continuous hemoperfusion".
1982
AbstractIngestion of paraquat results in an extremely dangerous poisoning. The first aim is to clear the gastrointestinal tract by inducing emesis and performing gastric/gut lavage; as much activated charcoal as possible should be administered per os and as quickly as possible. The best measure to eliminate paraquat from blood and tissue is hemoperfusion with coated activated charcoal; it has to be performed in the sense of “continuous hemoperfusion” about 8 h/d over a period of 2–3 weeks. These measures give a chance to lower the lethality of paraquat poisoning.
Versuche zur Herstellung linolsäurearmen Ölsäureesters über eine Hydrierung mit Palladium
1980
Uber eine Hydrierung mit Palladium auf Aktivkohle konnen geringe Gehalte an Linolsaure in Gegenwart eines hohen Olsaureuberschusses recht selektiv reduziert werden. Der Linolsauregehalt eines Fettsauremethylestergemisches wurde von 10% auf 2% gesenkt, dabei entstanden 3% cis-, 4% trans-Monoenfettsauren sowie 1% Stearinsaure. The Preparation of Oleic Ester with Reduced Linoleic Acid Content by Hydrogenation with Palladium By hydrogenation with palladium on charcoal low contents of linoleic acid can be reduced quite selectively in the presence of an excess of oleic acid ester. In a mixture of fatty acid methylesters the content of linoleic acid was reduced from 10% to 2% with the formation of…
Removal of hexavalent chromium from wastewaters by bone charcoal
1999
The adsorption of hexavalent chromium onto bone charcoal was studied as a function of time, amount of charcoal, pH, concentration of chromium and sample volume. The cross interference with other elements was also investigated. Tests were carried out with solutions of chromium(VI) at concentrations between 5 and 25 mg · L–1. Chromium removal efficiencies higher than 90% were achieved at pH = 1 using 2 g of bone charcoal and a stirring time in the order of 30 min. Acid and alkaline pretreatments of bone charcoal did not improve the sorption capacity of bone charcoal against Cr(VI). The presence of other ions had practically no influence on the chromium removal. The presence of a matrix of tan…
Effects of pyrolysis temperature on the hydrologically relevant porosity of willow biochar
2018
Biochar pore space consists of porosity of multiple length scales. In direct water holding applications like water storage for plant water uptake, the main interest is in micrometre-range porosity since these pores are able to store water that is easily available for plants. Gas adsorption measurements which are commonly used to characterize the physical pore structure of biochars are not able to quantify this pore-size range. While pyrogenetic porosity (i.e. pores formed during pyrolysis process) tends to increase with elevated process temperature, it is uncertain whether this change affects the pore space capable to store plant available water. In this study, we characterized biochar poro…
Combustible vegetal y etnografía: estudio de un horno de pan en Ghuala (Argelia)
2013
[ES] La maderas y los carbones constituyen un patrimonio biológico y cultural susceptible de ser analizado, tanto en contextos arqueológicos como etnográficos. La antracología, por medio del muestreo del carbón y su identificación botánica, aporta información sobre la interacción constante de los grupos humanos con la vegetación. Se presenta en este artículo un estudio etnográfico realizado en 2012 en Ghuala (Argelia), a través del análisis del combustible leñoso utilizado en un horno de pan tradicional de uso familiar, con el objetivo de arrojar mayor luz al debate existente en torno a las estrategias de gestión del combustible leñoso en las sociedades humanas del pasado. [EN] Wood and cha…