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Biofuels play an essential role in the global energy landscape, providing a renewable alternative for transportation fuels. In 2010, global biofuel production reached 105 billion liters, meeting 2.7% of the world's fuel demands, primarily through ethanol and biodiesel. The paper discusses the history of biofuel, focusing on vegetable oil-based fuels and their potential growth in significance as alternatives to fossil fuels.
Biocatalysis and …, 2008
Journal of the Brazilian Chemical Society, 2005
A importância da produção de biodiesel, nos últimos cinco anos, é apresentada a partir de artigos científicos publicados e patentes depositadas. Foi realizada uma análise crítica sobre as fontes oleaginosas mais utilizadas como matéria-prima para produção de biodiesel, os catalisadores e os métodos de acompanhamento da reação de transesterificação. Também foram avaliados estudos comparativos entre emissões de diesel fossil e misturas, em várias proporções, com biodiesel. Finalmente, foram indicados desafios enfocando aspectos tecnológicos, agronômicos e de infraestrutura para produção de biodiesel. The importance of biodiesel production was analyzed based on scientific articles and patents. A critical analysis was presented on the most used oil sources, the catalysts and the methods to verify the transesterification yields. Also analyzed were the comparative studies on emissions from pure fossil diesel and mixtures with biodiesel in variable proportions. Finally some challenges and considerations focused on technological, agronomic and infrastructure aspects of biodiesel production were indicated.
The increasing industrialization and motorization of the world has led to a steep rise in the demand of fossil fuel and associated environmental issues. Fossil fuels are obtained from limited reserves and will run out eventually. Therefore renewable and environmental-friendly energy substitutes such as bio fuels as well as fuel efficiency improving methods are required.
International journal of engineering research and technology, 2019
In the recent past, intensive studies on internal combustion engines has emerged with a view to obtaining higher rate of production of fuels from alternative sources. The increase in alternative fuel investigations is caused by two main factors; a rapid decrease in world petroleum reserves and important environmental concerns originating from exhaust emissions. Fast depletion of the viable alternative fuels. Diesel fuel is largely consumed by the transportation sector. Thermodynamic tests based on the engine performance evaluations have established the feasibility of using vegetable oils. It has been found that vegetable oils hold special promise in this regard, because they can be produced from the plants grown in rural areas. Vegetable oils from crops such as soya bean, peanut, sunflower, rape, palm, coconut, karanja, neem, cotton, mustard, jatropha, linseed and caster have been evaluated in many parts of the world in comparison with other non-edible oils. To solve energy and envi...
Bioresource Technology, 2001
Methyl, ethyl, 2-propyl and butyl esters were prepared from canola and linseed oils through transesteri®cation using KOH and/ or sodium alkoxides as catalysts. In addition, methyl and ethyl esters were prepared from rapeseed and sun¯ower oils using the same catalysts. Chemical composition of the esters was determined by HPLC for the class of lipids and by GC for fatty acid compositions. The bio-diesel esters were characterized for their physical and fuel properties including density, viscosity, iodine value, acid value, cloud point, pure point, gross heat of combustion and volatility. Methyl and ethyl esters prepared from a particular vegetable oil had similar viscosities, cloud points and pour points, whereas methyl, ethyl, 2-propyl and butyl esters derived from a particular vegetable oil had similar gross heating values. However, their densities, which were 2±7% higher than those of diesel fuels, statistically decreased in the order of methyl $ 2-propyl > ethyl > butyl esters. Butyl esters showed reduced cloud points ()6°C to )10°C) and pour points ()13°C to )16°C) similar to those of summer diesel fuel having cloud and pour points of )8°C and )15°C, respectively. The viscosities of bio-diesels (3:3±7:6 Â 10 À4 Pa s at 40°C) were much less than those of pure oils (22:4±45:1 Â 10 À4 Pa s at 40°C) and were twice those of summer and winter diesel fuels (3.50 and 1:72 Â 10 À4 Pa s at 40°C), and their gross heat contents of approximately 40 MJ/kg were 11% less than those of diesel fuels ($45 MJ/kg). For dierent esters from the same vegetable oil, methyl esters were the most volatile, and the volatility decreased as the alkyl group grew bulkier. However, the bio-diesels were considerably less volatile than the conventional diesel fuels. Ó
This evidence map provides an overview of Tai Chi research and describes its volume and focus. It combines a systematic review of systematic reviews with a scoping review for the VA priority areas pain, posttraumatic stress disorder, and fall prevention. The evidence map summarizes patient outcomes reported in reviews of studies in patients practicing Tai Chi for health-related indications. We searched PubMed, DARE, the Cochrane Library of Systematic Reviews, the Campbell Collaboration database, AMED, CINAHL, PsycInfo, Scopus, Web of Science, and PROSPERO; screened reviews of reviews; and consulted with topic experts. We used a bubble plot to graphically display the research field and summarized results narratively in an executive summary. Tai Chi has been investigated as a treatment for a number of clinical indications. The systematic review identified 107 systematic reviews. Reviews addressing general health effects, psychological wellbeing, or interventions in older adults included between 31 and 51 randomized controlled trials (RCTs). The topic areas balance, hypertension, falls, quality of life, cognitive performance, and vestibulopathy have also been the focus of research; included reviews identified 10 or more pertinent RCTs per topic. Statistically significant effects across existing studies were reported for hypertension, falls outside of institutions, cognitive performance, osteoarthritis, chronic obstructive pulmonary disease, pain, balance confidence, depression, and muscle strength. However, review authors cautioned that firm conclusions cannot be drawn due to methodological limitations in the original studies and/or an insufficient number of research studies.
2010
Research and Development (R&D) grants support research projects and seminars concerned with the interface between cultural policy, knowledge relating to historic environments and different scientific disciplines. Introduction 5 The Swedish National Heritage Board held a two-day workshop named "Removal of Damaging Conservation Treatments on Mural Paintings" on November 2 and 3, 2007 at Österbybruk and Vendel. The workshop was sponsored by "FoU-medel" (R&D funds), distributed by the Swedish National Heritage Board and from "Syskonen Bothéns stiftelse" distributed by "Nordiska konservatorförbundet Svenska sektionen" (NKF-S). This is the final report, which includes a summary of the presentations and discussions during the workshop. The main objective of the workshop was to discuss possible treatments of earlier destructive conservation treatments on mural paintings with special attention to the problems in Vendel Church in Uppland. Lecturers from Denmark, Germany and Italy were invited to share their experiences and to illustrate different solutions to similar problems. Another motivation for the workshop was that the Swedish National Heritage Board was working on the conservation of the medieval mural paintings in Vendel Church between 2005 and 2008. In 1930 the mural paintings were uncovered and treated with casein. The casein has become brittle and the paint layer is flaking severely. Thus, there are two problems to address: 1) the reattachment of the paint layer and 2) the reduction of the casein. The problem is quite difficult and one of the purposes of the workshop was to discuss the problem and share our experiences with the preinvestigation of the paintings.
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