| 1. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Cameron, Lachlan, et al.
(author)
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NAMAs and INDCs : Interactions and opportunities
- 2015
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Reports (other academic/artistic)abstract
- Countries representing more than 90 percent of global greenhouse gas emissions and population have submitted intendednationally determined contributions (INDCs) in anticipation of the 21st COP in Paris. In parallel, developing countries are designing at least 152 nationally appropriate mitigation actions (NAMAs) and 13 have secured implementation funding. Connecting these two concepts, more than a third of developing countries communicate a role for NAMAs in their INDCs. It is therefore vital to understand the potential role of NAMAs (here understood as specific actions) with respect to INDCs (which are often broader targets) and vice versa. This paper explores the links between NAMAs and INDCs with regard to various elements central to their implementation, including: access to finance; stakeholder engagement; sustainable development impacts; measurement, reporting and verification (MRV); and institutional frameworks.To avoid delaying mitigation action any further, it is important to keep momentum behind NAMAs. They represent one of the few tools at our disposal for countries to undertake mitigation actions, be recognised for these efforts, and mobilise climate finance and investment. The skills and learning on NAMA development can be seen more fundamentally as capacity for the design of bottom-up actions. Attention should be paid now to ensure that this capacity is maintained in the future. To do this, continued attention must be paid to NAMAs in Paris, as a key implementation tool for INDCs and, therefore, a key element of the success of a new global climate agreement.
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| 3. |
- Diener, Silvia, et al.
(author)
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Accelerated carbonation of ashes and steel slags in a landfill cover construction
- 2008
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In: Proceedings of Second International Conference on Accelerated Carbonation for Environmental and Materials Engineering. - : University of Rome "La Sapienza". ; , s. 389-400
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Conference paper (peer-reviewed)abstract
- Fly ash from biofuel incineration and slags from steel production were used in two full scale applications of cover constructions on municipal solid waste (MSW) landfills. The long-term stability of the cover materials is studied in a designed laboratory experiment. The impact of six environmental factors on accelerated carbonation is investigated over a period of three years. Leaching behaviour, acid neutralization capacity, mineral composition (XRD) and thermo gravimetrical behaviour (TG) are tested after different periods of ageing under different conditions. By now samples were taken after three and ten months of ageing. Multivariate data analysis was used for data evaluation. The results indicate the factors material, ageing time and carbon dioxide content of the atmosphere to be most relevant.
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| 4. |
- Diener, Silvia, et al.
(author)
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Accelerated carbonation of steel slags in a landfill cover construction
- 2010
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In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 30:1, s. 132-139
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Journal article (peer-reviewed)abstract
- Steel slags from high-alloyed tool steel production were used in a full scale cover construction of a municipal solid waste (MSW) landfill. In order to study the long-term stability of the steel slags within the final cover, a laboratory experiment was performed. The effect on the ageing process, due to i.e. carbonation, exerted by five different factors resembling both the material characteristics and the environmental conditions is investigated. Leaching behaviour, acid neutralization capacity and mineralogy (evaluated by means of X-ray diffraction, XRD, and thermogravimetry/differential thermal analysis, TG/DTA) are tested after different periods of ageing under different conditions.Samples aged for 3 and 10 months were evaluated in this paper. Multivariate data analysis was used for data evaluation. The results indicate that among the investigated factors, ageing time and carbon dioxide content of the atmosphere were able to exert the most relevant effect. However, further investigations are required in order to clarify the role of the temperature.
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| 5. |
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| 6. |
- Diener, Silvia, et al.
(author)
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Mineral transformations in steel slag used as landfill cover liner material
- 2007
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In: SARDINIA 2007. - Cagliari : CISA, Environmental Sanitary Engineering Centre. - 9788862650038
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Conference paper (peer-reviewed)abstract
- In Europe, 15.2 million tonnes of steel slags have been generated in 2004 (Euroslag, 2006) out if which almost 6 million tonnes came from electric arc furnace (EAF) steelmaking and secondary metallurgical processes. In the presented project from Luleå University of Technology, two types of EAF slag and one slag originating from secondary metallurgical processes named ladle slag are investigated. The chemical and physical properties of these slags have been studied in detail (Herrmann, 2006; Andreas et al., 2005). For utilising steel slags in the liner of a landfill cover the long-term stability of the minerals is of great importance. Therefore, the ageing of steel slag minerals is evaluated with the help of a laboratory experiment. Particularly, the research questions, the experimental set-up and the methodology are presented. The present paper is part of a research project of the Division of Waste Science and Technology at Luleå University of Technology, Sweden in cooperation with Uddeholm Tooling AB, Hagfors municipality and MiMeR (Mineral and Metal Recycling Research Centre). It is investigated if steel slags are stable as a landfill cover liner material. The long-term stability is evaluated by determining the factors influencing the mineralogy of the slags and possible mineral transformations through ageing under the environmental conditions in a liner. The experiment includes two similar types of EAF slag and one ladle slag. Each steel slag sample is made by mixing 50% EAF slag and 50% ladle slag, addition of water and compaction. The specimens are stored in boxes under different atmospheric conditions. A reduced multivariate design has been chosen to determine the impact of different factors on the slag mineralogy. The factors that are varied in the experiment are relative humidity, carbon dioxide and temperature of the atmosphere surrounding the slag material as well as ageing time and the quality of the water used for sample making (see table 1). Table 1. Factorial design for ageing experiment of steel slagsLowMiddleHighRelative humidity30% -100%Carbon dioxide content0.036 (air)20 % * 100 %Temperature5 °C30 °C60 °CTime 1 month6 months1 yearWater quality destilled water -LeachateThe ageing of minerals is expected to initiate mineral transformations in steel slags. Primary phases will alter into secondary mineral phases. Changes in mineralogy can influence the stability of the liner. To evaluate mineralogy and properties of the aged steel slag, different analyses will be performed after the storage time of the specimens. X-ray diffraction and scanning electron microscopy as well as shear strength, acid neutralisation capacity and cation exchange capacity will be included. A possible mineral transformation for an alkaline material as steel slags can be the reaction of calcium ions from calcium silicates with the carbon dioxide resulting in the precipitation of calcium carbonate. Through this carbonation reaction, the transport of carbon dioxide into the bulk of the specimen could be hindered by the reaction products. Therefore, surface morphology can influence mineral transformations. First results and evaluations will be presented at the conference. REFERENCES Andreas L., Herrmann I., Lidstrom-Larsson M. & Lagerkvist A. (2005) Physical properties of steel slag to be reused in a landfill cover, Sardinia 2005, Tenth International Waste Management and Landfill Symposium, S. Margherita di Pula, Cagliari, Italy; 3 - 7 October 2005Euroslag (2006) Legal status of Slags. Position Paper. January 2006. The European Slag Association - EUROSLAG. Duisburg, Germany.Herrmann I. (2006). Use of Secondary Construction Material in Landfill Cover Liners. Licentiate Thesis. Luleå University of Technology, Sweden.
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| 9. |
- Hamisi, Rajabu, 1978-, et al.
(author)
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Reactive transport modelling of long-term phosphorus dynamic in the compact constructed wetland using COMSOL Multiphysics
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In: Ecological Engineering Journal.
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Journal article (other academic/artistic)abstract
- A three-dimensional reactive transport model (RETRAP-3D) was developed by this study in the COMSOL Multiphysics®software to evaluate the long-term sorption capacity and mechanisms of dissolved reactive phosphorus removal in reactive adsorbent. The model coupledphysics interfaces for water flow, transport of reactive species, reaction kinetics for chemical compositions and biofilm development. Simulations were conducted for Polonite®, Filtralite P®, and Blast Furnace Slag mediaat fully saturated media, equilibrium miscible solution and isothermal heat transfer conditions. The model was validated using column experimental data ofsimilar media for application in constructed filter beds. The general modelling results showed good agreement with the measured breakthrough data. The most significant DIP retention capacity (P < 0.02) and longest residence time(1250 days) has been found for Polonite® and the most insignificant DIP retention for blast furnace slag (P > 0.54). The DIP removal was significantly correlated to factors of pH change, media characteristics, hydraulic dosage and retention times. These results demonstrate the reliability of the model as aflexible tool to predict the long-term performance of filter media and better understand processes within the system under various operational, weather and wastewater conditions.
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| 10. |
- Herrmann, Björn, et al.
(author)
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Emergence and Spread of Chlamydia trachomatis Variant, Sweden
- 2008
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In: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 14:9, s. 1462-1465
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Journal article (peer-reviewed)abstract
- A variant of Chlamydia trachomatis that had escaped detection by commonly used systems was discovered in Sweden in 2006. In a nationwide study, we found that it is now prevalent across Sweden, irrespective of the detection system used. Genetic analysis by multilocus sequence typing identified a predominant variant, suggesting recent emergence.
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