181 research outputs found
Chemical attributes of an Argisoil of the Vale do São Francisco after melon growth with phosphate and potash rocks biofertilizers.
A aplicação de fertilizantes pode promover mudanças na reação do solo e na disponibilidade de nutrientes importantes para as plantas. A produção de biofertilizantes a partir de rochas é um processo prático que reduz o consumo de energia e aumenta a disponibilidade de nutrientes no solo. Em experimento de campo foram avaliados os efeitos de biofertilizantes produzidos com rochas, além do enxofre elementar inoculado com Acidithiobacillus , em atributos químicos de um Argissolo do Vale do São Francisco após cultivo do melão, em comparação com fertilizantes minerais solúveis. Usou-se o fatorial 3 2+2, em blocos casualizados, com biofertilizante fosfatado (PB) e potássico (KB), em quantidades correspondentes à adição de superfosfato simples (SS) e cloreto de potássio (KCl), o dobro e o triplo da recomendação. Foram usados tratamentos adicionais com SS+KCl na quantidade recomendada e o controle sem adição de P e K (P0K0). Os biofertilizantes reduziram o pH do solo, e os teores mais elevados de P e K disponíveis foram obtidos com aplicação de PB e KB nas doses mais elevadas. Os maiores teores de Mg foram obtidos com o biofertilizante KB na dose 240 kg ha -1, em função da liberação de Mg da biotita. Os biofertilizantes de rochas com P e K podem ser usados como alternativa a fertilizantes solúveis, devido ao maior efeito residual para P, Ca e Mg do solo, especialmente em solos alcalinos ou para solos ácidos após a calagem
Marine plastics threaten giant Atlantic Marine Protected Areas.
There has been a recent shift in global perception of plastics in the environment, resulting in a call for greater action. Science and the popular media have highlighted plastic as an increasing stressor [1,2]. Efforts have been made to confer protected status to some remote locations, forming some of the world's largest Marine Protected Areas, including several UK overseas territories. We assessed plastic at these remote Atlantic Marine Protected Areas, surveying the shore, sea surface, water column and seabed, and found drastic changes from 2013-2018. Working from the RRS James Clark Ross at Ascension, St. Helena, Tristan da Cunha, Gough and the Falkland Islands (Figure 1A), we showed that marine debris on beaches has increased more than 10 fold in the past decade. Sea surface plastics have also increased, with in-water plastics occurring at densities of 0.1 items m-3; plastics on seabeds were observed at ≤ 0.01 items m-2. For the first time, beach densities of plastics at remote South Atlantic sites approached those at industrialised North Atlantic sites. This increase even occurs hundreds of meters down on seamounts. We also investigated plastic incidence in 2,243 animals (comprising 26 species) across remote South Atlantic oceanic food webs, ranging from plankton to seabirds. We found that plastics had been ingested by primary consumers (zooplankton) to top predators (seabirds) at high rates. These findings suggest that MPA status will not mitigate the threat of plastic proliferation to this rich, unique and threatened biodiversity
Production of ethanol from mesquite ( Prosopis juliflora (SW) D.C.) pods mash by Zymomonas mobilis and Saccharomyces cerevisiae
This study aimed to assess the use of mesquite pods hydrated mash as
biomass for the growth of Saccharomyces cerevisiae UFEPEDA-1012 and
Zymomonas mobilis UFEPEDA-205 and for ethanol production using a
submerged fermentation. A 23 factorial design was used to analyze the
effects of the type of microorganism, time of fermentation and
condition of cultivation on the ethanol production in mesquite pods
mash (30 g 100 mL-1). From the obtained results the hydrated mesquite
pods mash presented as a good substrate for the growth of S. cerevisiae
and Z. mobilis in comparison to the standard media. The effect that
most affected the ethanol production was the type of microorganism. The
highest ethanol concentration (141.1 gL-1) was found when Z. mobilis
was cultivated in mesquite pods mash under static condition for 36 hrs.
Ethanol production by S. cerevisiae was higher (44.32 gL-1) after 18
hrs of fermentation under static condition. According to these results,
the mesquite pods could be known as an alternative substrate to be used
for biotechnological purposes, mainly for ethanol production
Liquefied natural gas for the UK: a life cycle assessment
PURPOSE: Liquefied natural gas (LNG) is expected to become an important component of the UK’s energy supply because the national hydrocarbon reserves on the continental shelf have started diminishing. However, use of any carbon-based fuel runs counter to mitigation of greenhouse gas emissions (GHGs). Hence, a broad environmental assessment to analyse the import of LNG to the UK is required.
METHODS: A cradle to gate life cycle assessment has been carried out of a specific but representative case: LNG imported to the UK from Qatar. The analysis covers the supply chain, from gas extraction through to distribution to the end-user, assuming state-of-the-art facilities and ships. A sensitivity analysis was also conducted on key parameters including the energy requirements of the liquefaction and vaporisation processes, fuel for propulsion, shipping distance, tanker volume and composition of raw gas.
RESULTS AND DISCUSSION: All environmental indicators of the CML methodology were analysed. The processes of liquefaction, LNG transport and evaporation determine more than 50% of the cradle to gate global warming potential (GWP). When 1% of the total gas delivered is vented as methane emissions leakage throughout the supply chain, the GWP increases by 15% compared to the GWP of the base scenario. The variation of the GWP increases to 78% compared to the base scenario when 5% of the delivered gas is considered to be lost as vented emissions. For all the scenarios analysed, more than 75% of the total acidification potential (AP) is due to the sweetening of the natural gas before liquefaction. Direct emissions from transport always determine between 25 and 49% of the total eutrophication potential (EP) whereas the operation and maintenance of the sending ports strongly influences the fresh water aquatic ecotoxicity potential (FAETP).
CONCLUSIONS: The study highlights long-distance transport of LNG and natural gas processing, including sweetening, liquefaction and vaporisation, as the key operations that strongly affect the life cycle impacts. Those cannot be considered negligible when the environmental burdens of the LNG supply chain are considered. Furthermore, the effect of possible fugitive methane emissions along the supply chain are critical for the impact of operations such as extraction, liquefaction, storage before transport, transport itself and evaporation
Estudos sobre a nutrição mineral do milho. II. Efeito de doses crescentes de N, P e K no crescimento, produção e composição mineral da variedade Piranão em condições controladas.
O milho, var. Piranao, foi cultivado em solucao nutritiva com niveis crescentes de N, P e K. Houve resposta linear a adicao de N e assintotica as doses de P e de K. A determinacao a atividade da reductase de nitrato se correlacionou melhor com a producao total nas folhas, por sua vez refletiu melhor o estado nutricional que a determinacao de putrescina nas folhas
Interaction Between Convection and Pulsation
This article reviews our current understanding of modelling convection
dynamics in stars. Several semi-analytical time-dependent convection models
have been proposed for pulsating one-dimensional stellar structures with
different formulations for how the convective turbulent velocity field couples
with the global stellar oscillations. In this review we put emphasis on two,
widely used, time-dependent convection formulations for estimating pulsation
properties in one-dimensional stellar models. Applications to pulsating stars
are presented with results for oscillation properties, such as the effects of
convection dynamics on the oscillation frequencies, or the stability of
pulsation modes, in classical pulsators and in stars supporting solar-type
oscillations.Comment: Invited review article for Living Reviews in Solar Physics. 88 pages,
14 figure
Asteroseismology and Interferometry
Asteroseismology provides us with a unique opportunity to improve our
understanding of stellar structure and evolution. Recent developments,
including the first systematic studies of solar-like pulsators, have boosted
the impact of this field of research within Astrophysics and have led to a
significant increase in the size of the research community. In the present
paper we start by reviewing the basic observational and theoretical properties
of classical and solar-like pulsators and present results from some of the most
recent and outstanding studies of these stars. We centre our review on those
classes of pulsators for which interferometric studies are expected to provide
a significant input. We discuss current limitations to asteroseismic studies,
including difficulties in mode identification and in the accurate determination
of global parameters of pulsating stars, and, after a brief review of those
aspects of interferometry that are most relevant in this context, anticipate
how interferometric observations may contribute to overcome these limitations.
Moreover, we present results of recent pilot studies of pulsating stars
involving both asteroseismic and interferometric constraints and look into the
future, summarizing ongoing efforts concerning the development of future
instruments and satellite missions which are expected to have an impact in this
field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume
14, Issue 3-4, pp. 217-36
An environmental evaluation of food waste downstream management options: a hybrid LCA approach
Food waste treatment methods have been typically analysed using current energy generation conditions. To correctly evaluate treatment methods, they must be compared under existing and potential decarbonisation scenarios. This paper holistically quantifies the environmental impacts of three food waste downstream management options—incineration, composting, and anaerobic digestion (AD).
Methods
The assessment was carried out using a novel hybrid input–output-based life cycle assessment method (LCA), for 2014, and in a future decarbonised economy. The method introduces expanded system boundaries which reduced the level of incompleteness, a previous limitation of process-based LCA.
Results
Using the 2014 UK energy mix, composting achieved the best score for seven of 14 environmental impacts, while AD scored second best for ten. Incineration had the highest environmental burdens in six impacts. Uncertainties in the LCA data made it difficult determine best treatment option. There was significant environmental impact from capital goods, meaning current treatment facilities should be used for their full lifespan. Hybrid IO LCA’s included additional processes and reduced truncation error increasing overall captured environmental impacts of composting, AD, and incineration by 26, 10 and 26%, respectively. Sensitivity and Monte Carlo analysis evaluate the methods robustness and illustrate the uncertainty of current LCA methods. Major implication: hybrid IO-LCA approaches must become the new norm for LCA.
Conclusion
This study provided a deeper insight of the overall environmental performance of downstream food waste treatment options including ecological burdens associated with capital goods.
Keywords
Anaerobic digestion Incineration Composting Food waste Hybrid life cycle assessment Capital good
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