| 1. |
- Andersson, F., et al.
(författare)
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Deblending seismic data by directionality penalties
- 2016
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Ingår i: 78th EAGE Conference and Exhibition 2016: Efficient Use of Technology - Unlocking Potential. - : European Association of Geoscientists & Engineers. - 9789462821859
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Konferensbidrag (refereegranskat)abstract
- In conventional seismic surveys, there is a waiting time between sequentially fired shots. This time is determined such that the deepest reflection of interest is recorded before the following source is fired. In a survey with simultaneous or blended sources, the waiting time between the firing of shots is not dependent on the deepest reflection of interest, it is usually much shorter and/or can have random time delays. Thus, the wavefields due to independent sources are overlapped in the records. The blended data exhibit strong discontinuities in the source direction, in contrast to the coherency expected from seismic measurements. A strategy for deblending could then be to suppress these discontinuities. In this paper, we propose to do this by designing an energy functional that uses a combination of individual functionals that penalize deviations from local plane waves in the reconstructed (deblended) data, as well as a least squares term that penalizes discrepancies between the deblended and the measured data. In this way, we derive a set of coupled nonlinear partial differential equations that we use for the deblending procedure.
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| 2. |
- Gaur, V K, et al.
(författare)
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Sustainable strategies for combating hydrocarbon pollution : Special emphasis on mobil oil bioremediation
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 832
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Tidskriftsartikel (refereegranskat)abstract
- The global rise in industrialization and vehicularization has led to the increasing trend in the use of different crude oil types. Among these mobil oil has major application in automobiles and different machines. The combustion of mobil oil renders a non-usable form that ultimately enters the environment thereby causing problems to environmental health. The aliphatic and aromatic hydrocarbon fraction of mobil oil has serious human and environmental health hazards. These components upon interaction with soil affect its fertility and microbial diversity. The recent advancement in the omics approach viz. metagenomics, metatranscriptomics and metaproteomics has led to increased efficiency for the use of microbial based remediation strategy. Additionally, the use of biosurfactants further aids in increasing the bioavailability and thus biodegradation of crude oil constituents. The combination of more than one approach could serve as an effective tool for efficient reduction of oil contamination from diverse ecosystems. To the best of our knowledge only a few publications on mobil oil have been published in the last decade. This systematic review could be extremely useful in designing a micro-bioremediation strategy for aquatic and terrestrial ecosystems contaminated with mobil oil or petroleum hydrocarbons that is both efficient and feasible. The state-of-art information and future research
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| 3. |
- Guldris Leon, Lorena, 1983, et al.
(författare)
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Analysis of the concentration in rare metal ores during compression crushing
- 2018
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 120, s. 7-18
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Tidskriftsartikel (refereegranskat)abstract
- Given the increasing global demand for rare metals, there is a need for the development of fundamental predictive models to improve extraction processes. Comminution models commonly predict particle size reduction based on the compressive breakage behaviour; however, few of them include mineral concentration or mineral liberation at a coarse scale. This paper focuses on developing a model to predict the mineral concentration of rare metals as a function of the particle size distribution after a cycle of the compression crushing process. In this study, compressive breakage and geochemical analysis experiments were conducted on four different rare metal ores of tantalum and tungsten. The work is divided into two stages: the methodology of modelling particle size and modelling concentration by selecting a bimodal Weibull distribution for calibration. A novel model for simulating the concentration of rare metals as a function of the compression ratio is presented.
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| 4. |
- Guldris Leon, Lorena, 1983, et al.
(författare)
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Understanding Mineral Liberation during Crushing Using Grade-by-Size Analysis - A Case Study of the Penuota Sn-Ta Mineralization, Spain
- 2020
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Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Coarse comminution test-work and modeling are powerful tools in the design and optimization of mineral processing plants and provide information on energy consumption. Additional information on mineral liberation characteristics can be used for assessing the potential of pre-concentration stages or screens in the plant design. In ores of high-value metals (e.g., Ta, W), standard techniques-such as the mineralogical quantification of grain mounts by quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) or chemical analysis by X-ray fluorescence (XRF) can be challenging, due to the low relative abundance of such valuable minerals. The cost of QEMSCAN is also a limiting factor, especially considering the large number of samples required for the optimization of coarse comminution. In this study, we present an extended analytical protocol to a well-established mechanical test of interparticle breakage to improve the assessment of coarse mineral liberation characteristics. The liberation of ore minerals is a function of the rock texture and the difference in size and mechanical properties of the valuable minerals relative to gangue minerals and they may fraction in certain grain sizes if they behave differently during comminution. By analyzing the bulk-chemistry of the different grain size fractions produced after compressional testing, and by generating element by size diagrams, it is possible to understand the liberation characteristics of an ore. We show, based on a case study performed on a tantalum ore deposit, that element distribution can be used to study the influence of mechanical parameters on mineral liberation. This information can direct further mineralogical investigation and test work.
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| 5. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Quantifying shedding of synthetic fibers from textiles; a source of microplastics released into the environment
- 2018
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 25:2, s. 1191-1199
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Tidskriftsartikel (refereegranskat)abstract
- Microplastics in the environment are a subject of intense research as they pose a potential threat to marine organisms. Plastic fibers from textiles have been indicated as a major source of this type of contaminant, entering the oceans via wastewater and diverse non-point sources. Their presence is also documented in terrestrial samples. In this study, the amount of microfibers shedding from synthetic textiles was measured for three materials (acrylic, nylon, polyester), knit using different gauges and techniques. All textiles were found to shed, but polyester fleece fabrics shed the greatest amounts, averaging 7360 fibers/m(-2)/L-1 in one wash, compared with polyester fabrics which shed 87 fibers/m(-2)/L-1. We found that loose textile constructions shed more, as did worn fabrics, and high twist yarns are to be preferred for shed reduction. Since fiber from clothing is a potentially important source of microplastics, we suggest that smarter textile construction, prewashing and vacuum exhaustion at production sites, and use of more efficient filters in household washing machines could help mitigate this problem.
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| 6. |
- Dessne, Petter, et al.
(författare)
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Miljöstrategiska val för ett stärkt Borås
- 2012
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Ingår i: Borås Tidning. - : AB Boraas Tidning. - 1103-9132.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Vindkraften, stadstrafiken och järnvägen utgör tre problem eller tre möjligheter för Borås framtid. Vi föreslår några strategiska val för att stärka vår hemregion.
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| 7. |
- Ekström, Karin M, et al.
(författare)
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Looking into the kaleidoscope : different views on reuse and recycling of clothes
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A major environmental problem in Sweden is the fact that clothes are disposed of in the garbage rather than being reused or recycled. A study (Carlsson et al. 2011) indicates that 8 kg textiles are disposed of in the garbage per individual and year. Another study (Gustafsson and Ekström 2012) shows that 62 percent of the Swedes dispose usable clothes in the garbage. From an environmental perspective, it would be more beneficial to reuse or recycle textiles. In addition, producing textiles requires natural resources. For example, in order to produce 1 kg cotton, it takes between 7.000-29.000 litre water and between 0,3 to 1 kg oil (Fletcher 2008). Factors contributing to the high amount of clothes disposed of are an emphasis on fast fashion, low prices, increased welfare as well as more consumers following the fashion. However, this pattern of consumption is not sustainable in the long run (Ekström et al. 2012). The purpose of this paper is to increase the understanding of how clothing consumption can be more sustainable by demonstrating how a network consisting of different clothing retailers, recycling companies, charity organizations, consumer organizations, environmental organizations, branch organizations and authorities discuss and deal with this problem. The paper focuses on how they work with reuse and recycling today, but also on what they consider as important, for themselves as well as others, to do in the future in order to increase the level of reuse and recycling of clothes. The empirical data is based on a survey as well as the results from six one- day meetings in the network over 1,5 years time. The results show that there are individual as well as collaborative ways to deal with the problem. The participants in the network agree upon several things. First of all, they recognise the need that all the actors in the network have to contribute and collaborate to solve the problem. Second, there has to be long term solutions that are both environmentally as well as financially sound. Third, a consumer perspective that centres on solutions that enables consumers to act more environmentally friendly is a prerequisite in order to reduce disposal of clothes in the garbage and instead increase reuse and recycling. Finally, the role of marketing is pervasive for succeeding to solve this problem both by making the consumers aware of the effects clothes disposal have on the environment, but also by communicating to the consumer that there are alternative ways to dispose of clothes such as reuse and recycling. In order to approach the problem of how consumption can be more sustainable, a kaleidoscopic outlook presenting different views and solutions is suggested.
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| 8. |
- Abila, R., et al.
(författare)
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Oil extraction imperils Africa’s Great Lakes
- 2016
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 354:6312, s. 561-562
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- As the world's demands for hydrocarbons increase (1), remote areas previously made inaccessible by technological limitations are now being prospected for oil and gas deposits. Virtually unnoticed by the public, such activities are ongoing in the East African Great Lakes region, threatening these ecosystems famed for their hyper-diverse biota, including the unique adaptive radiations of cichlid fishes (2). Countries in the region see exploitation of hydrocarbon reserves as a vital economic opportunity. In the Lake Albert region of Uganda, for example, the government foresees a $3.6 billion oil profit per year starting in 2018—a sum almost as high as the country's current annual budget (3). However, oil extraction in the East African Great Lakes region poses grave risks to the environment and local communities.
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| 9. |
- Bengtsson, Magnus, 1973, et al.
(författare)
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Modelling of output and power consumption in vertical shaft impact crushers
- 2008
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Ingår i: International Journal of Mineral Processing. - : Elsevier BV. - 0301-7516 .- 1879-3525. ; 88:1-2, s. 18-23
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Tidskriftsartikel (refereegranskat)abstract
- The vertical shaft impact (VSI) crusher is a commonly-used machine in aggregate production. A comprehensive understanding of the physical phenomena that influence the power consumption and the particle output of the device are essential to enable development of protocols that minimize energy consumption during rock crushing.While natural gravel has traditionally been the main choice of material for Swedish concrete manufacturers, the number of deposits is limited due to its role as a fresh water filter. It is therefore essential to achieve a product size distribution of aggregate that is on the same order as that of natural gravel to enable its use in concrete production.This work aims to present a model that predicts capacity, power and particle size distribution in a VSI crusher.
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| 10. |
- Bengtsson, Magnus, 1973, et al.
(författare)
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Size and shape simulation in a tertiary crushing stage, a multi objective perspective
- 2015
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 77, s. 72-77
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing demand to optimise yield and increase capacity of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and recent research has shown that the quality aspects of production have great influence on the optimisation results. The quality and capacity of a product is influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimisation software.In this paper, a novel approach to analyse the parameters product capacity and quality is presented. As an example a cone crusher and a vertical shaft impact crusher (VSI) is simulated in a tertiary stage. The simulation shows how capacity and product quality for a range of products will be affected when a parameter is changed. The paper also shows how wear will affect product capacity and quality.
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