1,721,023 research outputs found
Biokerosene Production from Bio-Chemical and Thermo-Chemical Biomass Conversion and Subsequent Fischer-Tropsch Synthesis
No full textSynthetic fuels derived from synthesis gas provided from gasification of solid fuels using the Fischer-Tropsch Synthesis are well-known and used since the 1920's. The initial process used coal as feedstock to produce mainly diesel like fuels when crude oil was not at hand. Nowadays and especially in the context of alternative and climate friendly fuels new process chains are taken into consideration based on this overall principle. This includes the production of "green" syngas by biomass gasification or reforming of bio-methane from e.g. biogas plants based on a biochemical biomass conversion. Against this background the overall goal of this paper is to give an overview of the current state of these two syngas provision pathways and the subsequent synthesis options, mainly focusing on the Fischer-Tropsch Synthesis. The overall process chains can be categorized into the Biomass-to-Liquids (BtL) and the Biogas-to-Liquids (Bio-GtL) pathways
Past and future developments of the global air traffic
No full textThis paper gives an overview of the development and structure of the global and regional air traffic markets. The number and geographical distribution of flights together with the aircraft types needed to satisfy the demand for passenger and cargo transport are analyzed. Air traffic market developments are described from a traffic-oriented perspective. Environmental and economic aspects are not subject of this discussion. Thus this paper addresses the following six topics: global development of the air transport system, regional distribution of the air traffic, airport development and bottlenecks, airlines, aircraft types, and outlook of air traffic developmen
Climate Impacts of Aviation and the Potential of Aviation Powerfuels Toward Their Mitigation
Get PDFThe UN Conference of the Parties, representing nearly all UN member states, agreed in the Paris Agreement to “hold the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels”. The International Civil Aviation Organization (ICAO) and the International Air Transport Association (IATA) have set a “Net-Zero Carbon Emissions” target by 2050. While the Paris Agreement focuses on limiting global temperature increase, the aviation industry targets primarily address CO2 emissions. However, aviation’s climate impact extends beyond CO2 to contrails and indirect effects of nitrogen oxide (NOx) emissions. Research shows that only one-third of aviation’s climate impact (in terms of effective radiative forcing, ERF) is due to CO2, with the remaining two-thirds from the other non-CO2-related cliamte impacts. The largest climate impacts of aviation, by magnitude, are contrails, CO2 emissions, and NOx effects. Addressing only CO2 emissions would overlook a significant portion of aviation’s climate impact, making it essential to consider all related climate factors to align aviation industry targets with the Paris Agreement. This chapter first describes aviation’s climate effects and then explores how increased use of powerfuels as example for renewably sourced kerosene might influence its overall climate impact
Powerfuels and Alternative Fuels in the Maritime Sector
No full textThe maritime sector accounts for about 3% of global GHG emissions and largely depends on fossil fuels like heavy fuel oil (HFO), marine diesel oil (MDO), and marine gas oil (MGO). These fuels contribute to significant emissions of greenhouse gases (CO2, CH4) and pollutants such as particulate matter (PM), sulfur oxides (SO2), and nitrogen oxides (NOx). To address these emissions, various regulations have been implemented by nations, regional bodies like the EU, and internationally by the International Maritime Organization (IMO), which sets global standards for safety, security, and environmental performance. While MARPOL Annex VI has regulated NOx, SO2, and energy efficiency since 2005, reducing GHG emissions has gained more focus recently. Adopting alternative fuels is considered the most viable strategy for reducing vessel GHG emissions. Various alternative fuels, each with unique benefits, challenges, and infrastructure requirements, are explored in this article, including liquefied natural gas (LNG), liquefied petroleum gas (LPG), methanol, ammonia, hydrogen, and bio-based or electricity-based diesel fuels. Their properties and technical applications, such as fuel storage and propulsion system compatibility, are discussed, along with regulatory and suitability considerations for reducing GHG emissions in the maritime industry
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Hydrogen transport and storage options
No full textIn this article, different options for storage and transportation of hydrogen are discussed.
First, different technologies, which are currently technically mature, are explained. Subsequently, these technologies are compared on the basis of different technical parameters. In addition, for the different technologies the
variants and differences are explained. Also, it is discussed which storage technology is best suited for specific applications.
Finally, an impression
about the influence about the main cost driver for the different systems is given
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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