Search results for "fossil"
showing 10 items of 412 documents
Exploring the major depletions of conodont diversity during the Triassic
2014
International audience; In this paper, we show that the Triassic fossil record reflects just two great depletions of conodont diversity before the Rhaetian, which occurred in the Smithian (Olenekian, Early Triassic) and in the Julian (Carnian, Late Triassic). By exploring this context, our results highlighted that they respond to different origination?extinction dynamics. Thus, while the Smithian diversity depletion can be interpreted as a consequence of elevated extinction, the Julian diversity depletion was triggered by fluctuations in origination regime. This evidence suggests that, despite the role of extinction on diversity losses, conodonts suffered crucial changes on the origination …
Gladius-bearing coleoids from the Upper Cretaceous Lebanese Lagerstätten: diversity, morphology, and phylogenetic implications.
2017
AbstractGladius-bearing coleoids are rare in the fossil record. For the Cretaceous period, these cephalopods are mainly recorded in a few Lagerstätten in Lebanon (Haqel, Hajoula, En Nammoura, and Sahel Aalma). Here, we study 16 specimens of gladius-bearing coleoids from these Upper Cretaceous Lebanese Lagerstätten to investigate their taxonomic diversity. Besides two species that were already reported (Dorateuthis syriacaandGlyphiteuthis libanotica), one new species is identified in the Cenomanian site of Hajoula:Rachiteuthis acutalin. sp., as well as another form ofGlyphiteuthisfrom En Nammoura. Several studied specimens exhibit well-preserved soft-part characters. Among them, we document …
Fossil remains of Macaca sylvanus florentina (Cocchi, 1872) (Primates, Cercopithecidae) from the Early Pleistocene of Quibas (Murcia, Spain)
2011
The macaque material from the Early Pleistocene site of Quibas (Albanilla, Murcia, Spain), including dentognathic remains, isolated teeth and some postcranial bone fragments, is described. Both metrically and morphologically, this sample must be attributed to Macaca sylvanus (the Barbary macaque). This species is currently distributed through North Africa and Gibraltar, but was much more widely distributed during the Plio-Pleistocene, being represented by several European fossil subspecies. Metrical comparisons of dental size and proportions between extant M. s. sylvanus and fossil Macaca sylvanus florentina from the type locality and other Italian sites are undertaken, in order to classify…
Local Green Power Supply Plants Based on Alcohol Regenerative Gas Turbines: Economic and Environmental Aspects
2020
Growing economies need green and renewable energy. Their financial development can reduce energy consumption (through energy-efficient technologies) and replace fossil fuels with renewable ones. Gas turbine engines are widely used in transport and industry. To improve their economic attractiveness and to reduce harmful emissions, including greenhouse gases, alternative fuels and waste heat recovery technologies can be used. A promising direction is the use of alcohol and thermo-chemical recuperation. The purpose of this study is to estimate the economic efficiency and carbon dioxide emissions of an alcohol-fueled regenerative gas turbine engine with thermo-chemical recuperation. The carbon …
The Physical Economy of France (1830–2015). The History of a Parasite?
2019
Abstract This article explores long-term trends and patterns of material use in France for a 185-year period. It is the first long-term study of material flows for France with national and yearly data for most of the period. Based on a material flow analysis (MFA) that is fully consistent with current standards of economy-wide MFAs and covers domestic extraction, imports, and exports of materials, we investigated the evolution of the French metabolism from industrialization to financialized capitalism. Over the whole period, there is a 9-fold increase in domestic material consumption, an expansion of material use per capita, and a spectacular addition of abiotic resources (fossil fuels and …
Development of net energy ratio and emission factor for quad-generation pathways
2014
Published version of an article in the journal: Energy Systems. Also available from the publisher at: http://dx.doi.org/10.1007/s12667-014-0126-4 The conversion of biomass to four different outputs via gasification is a renewable technology that could reduce the use of fossil fuels and greenhouse gas (GHG) emissions. This study investigates the energy aspects for a new concept of biomass based quad-generation plant producing power, heat, methanol and methane. Circulating fluidized bed gasifier and the gas technology institute (GTI) gasifier technologies are used for this quad-generation process. Two different biomass feedstocks are considered in this study. The net energy ratio for six diff…
Renewable electricity producing technologies and metal depletion: A sensitivity analysis using the EROI
2015
International audience; More and more attention is being paid to renewable technologies because they are seen as a great opportunity to disengage our society from its dependence on fossil fuels. Such flow-based energy resources that rely on solarenergy are supposed to lead us toward a sustainable energy future. However, because of their high capitalintensity, renewable technologies require large amounts of matter, including both common and rare metals.These metals require energy for their production, and more specifically for their extraction. The energy costassociated with metal extraction is linked to mineral ore grade, meaning that as depletion progresses, energycost increases. In additi…
Perspective on hydrogen energy carrier and its automotive applications
2014
The paper outlines the concept of energy carrier with a particular reference to hydrogen, in view of a more disseminated employment in the field of automotive applications. In particular hydrogen production is analyzed considering the actual state of the art and recent technologies applied in production from the primary sources (fossil fuels, renewable energies, and water electrolysis). Then the problem of hydrogen storage is considered both from technical and economical point of views. In particular, differences between physical and chemical storage are here considered with a particular glance to the most innovative technologies including carbon nanostructures. A review on the main problem…
Refuse Derived Fuel Gasification Possibilities in Small Scale Units
2018
Fossil fuels use reduction and waste recycling are two great challenges facing our society nowadays. A concept intended to solve both problems is Waste-to-Energy (WtE) approach (Brunner and Rechberger in Waste Manag 37: 3–12, 2015). The routes to the energy recovery can be grouped as thermo-chemical and biochemical approaches and the selection of the WtE technologies also depends on the waste composition. Waste sources can be industrial and agricultural production and urban regions but growing attention is paid to municipal solid waste in OECD countries (Hoornweg and Bhada-Tata in What a waste: a global review of solid waste management. World Bank, Washington, DC 2012) consisting dominantly…
Energy Saving in Public Transport Using Renewable Energy
2017
Hydrogen produced by renewable sources represents an interesting way to reduce the energetic dependence on fossil fuels in the transportation sector. This paper shows a feasibility study for the production, storage and distribution of hydrogen in the western Sicilian context, using three different renewable sources: wind, biomass and sea wave. The objective of this study is the evaluation of the hydrogen demand, needed to replace all diesel supplied buses with electrical buses equipped with fuel cells. An economic analysis is presented with the evaluation of the avoidable greenhouse gas emissions. Four different scenarios correlate the hydrogen demand for urban transport to the renewable en…