| 1. |
- Ahlberg, Erik, et al.
(författare)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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| 2. |
- Andersson, Linus, et al.
(författare)
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Reduced order modeling for the dynamic analysis of structures with nonlinear interfaces
- 2019
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Ingår i: COMPDYN 2019 - 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Proceedings. - 2623-3347. - 9786188284470 ; 2, s. 2395-2406
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Konferensbidrag (refereegranskat)abstract
- In the present paper, linear substructures with nonlinearities localized at their interfaces, such as the joints in a beam structure, are studied. By subdivision of the total structure into substructures, reduced subsystems are obtained by component mode synthesis. Nonlinear elements are introduced at supports or between substructures. A numerical example is presented where a beam subjected to blast loading is studied. The influence of the nonlinear behavior as well as the number of retained fixed-interface normal modes in the reduced subsystems are evaluated. The response is also compared to the response of equivalent single-degree-of-freedom systems, which are frequently employed in blast load design calculations. For the load cases studied, the displacement computed from an equivalent single-degree-of-freedom system correspond fairly well to the displacement given by a refined two-dimensional beam model, reduced by substructuring. In contrast, the shear force differs significantly due to that higher order modes are neglected in the single-degree-of-freedom system.
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| 3. |
- Chen, Jr-Tai, et al.
(författare)
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Room-Temperature mobility above 2200 cm2/V.s of two-dimensional electron gas in a sharp-interface AlGaN/GaN heterostructure
- 2015
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 106:25
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Tidskriftsartikel (refereegranskat)abstract
- A high mobility of 2250 cm2/V·s of a two-dimensional electron gas (2DEG) in a metalorganic chemical vapor deposition-grown AlGaN/GaN heterostructure was demonstrated. The mobility enhancement was a result of better electron confinement due to a sharp AlGaN/GaN interface, as confirmed by scanning transmission electron microscopy analysis, not owing to the formation of a traditional thin AlN exclusion layer. Moreover, we found that the electron mobility in the sharp-interface heterostructures can sustain above 2000 cm2/V·s for a wide range of 2DEG densities. Finally, it is promising that the sharp-interface AlGaN/GaN heterostructure would enable low contact resistance fabrication, less impurity-related scattering, and trapping than the AlGaN/AlN/GaN heterostructure, as the high-impurity-contained AlN is removed.
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| 4. |
- Edo, Mar, et al.
(författare)
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Assessment of chemical and material contamination in waste wood fuels : a case study ranging over nine years
- 2016
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Ingår i: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 49, s. 311-319
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Tidskriftsartikel (refereegranskat)abstract
- The increased demand for waste wood (WW) as fuel in Swedish co-combustion facilities during the last years has increased the import of this material. Each country has different laws governing the use of chemicals and therefore the composition of the fuel will likely change when combining WW from different origins. To cope with this, enhanced knowledge is needed on WW composition and the performance of pre-treatment techniques for reduction of its contaminants. In this study, the chemical and physical characteristics of 500 WW samples collected at a co-combustion facility in Sweden between 2004 and 2013 were investigated to determine the variation of contaminant content over time. Multivariate data analysis was used for the interpretation of the data. The concentrations of all the studied contaminants varied widely between sampling occasions, demonstrating the highly variable composition of WW fuels. The efficiency of sieving as a pre-treatment measure to reduce the levels of contaminants was not sufficient, revealing that sieving should be used in combination with other pre-treatment methods. The results from this case study provide knowledge on waste wood composition that may benefit its management. This knowledge can be applied for selection of the most suitable pre-treatments to obtain high quality sustainable WW fuels.
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| 5. |
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| 6. |
- Berg, Jessica, 1975-, et al.
(författare)
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Kombinerade mobilitetstjänster på landsbygd och i mindre tätorter : resultat från förstudien KomILand
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Att erbjuda olika typer av mobilitetstjänster för boende på landsbygd och i mindre tätorter kan ge ökad tillgänglighet och minskat behov av att resa med egen bil. Syftet med förstudien KomILand är att bereda uppstart för framtida demoprojekt för kombinerad mobilitet i landsbygder och i mindre tätorter med avseende på plats, användare, tjänster och finansiering. Flera aktiviteter har genomförts: Identifiering av geografiskt lämpliga områden; behovsanalys, identifiering av tjänstedesign och affärsmodeller samt mobilisering av lokalt och regionalt engagemang. Tjänster och affärsmodeller har tagits fram med hjälp av Osterwalder Business Model Canvas. Ett antal kriterier har tagits fram för vilka egenskaper en landsbygd eller mindre ort bör ha för att en kombination av flera mobilitetstjänster ska ha möjlighet att kunna fungera. De tjänster som tillsammans i ett tjänstepaket skulle kunna ingå i en kombinerad mobilitetstjänst för landsbygd har validerats teoretiskt i den fiktiva bygden Småtorp. En offentlig aktör bör tillhandahålla organisatoriska och digitala plattformar åt de lokala mottagarna samt KomILand-konsulenter. KomILand kan bidra med lönsamhet, sänka mobilitetskostnaderna för kunderna, bidra med nya kunder till kollektivtrafiken och leda till ökad hållbarhet för samhället, förutsatt att det finns en robust och kvalitativ kollektivtrafik i botten.
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| 7. |
- Berg, Jessica, et al.
(författare)
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Kombinerade mobilitetstjänster på landsbygd och i mindre tätorter– resultat från förstudien KomILand
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Different types of mobility services in small towns and rural areas can increase accessibility among theresidents and reduce the need to travel by one’s own car. The purpose of this pre-study is to preparefor future demonstration projects for combined mobility (CM) in small towns and rural areas byproviding data on location, users, services and financing. Several activities have been carried out:identification of geographically appropriate areas and ongoing projects worldwide; analysis of userneeds; identification of service design and business models; and mobilization of local and regionalinvolvement. Services and business models have been developed using The Osterwalder BusinessModel Canvas. Several characteristics have been identified that a small town or rural area should havein order for CM to function. Services that could be included in a service package in a CM rural servicehave been validated theoretically in the fictional town of Småtorp. A public actor needs to provideorganisational and digital platforms to local organisations, and KomILand-consultants. KomILand cancontribute profitability, reduce mobility costs for customers, contribute new customers to the publictransport operators, and lead to increased sustainability for society, if there is a robust and qualitativepublic transport system as a basis
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| 8. |
- Edo Gimenez, Mar, et al.
(författare)
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Fate of metals and emissions of organic pollutants from torrefaction of waste wood, MSW, and RDF
- 2017
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Ingår i: Waste Management. - Oxford : Elsevier. - 0956-053X .- 1879-2456. ; 68, s. 646-652
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Tidskriftsartikel (refereegranskat)abstract
- Torrefaction of municipal solid waste (MSW), refuse-derived fuel (RDF), and demolition and construction wood (DC) was performed at 220°C and a residence time of 90 min in a bench-scale reactor. The levels of toxic polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) contained in emission from the torrefaction process were evaluated. In addition, main ash-forming elements and trace metals in the raw feedstock and char were determined. The use of MSW in fuel blends with DC resulted in lower PCDD and PCDF emissions after torrefaction, compared with the RDF blends. The migration of chlorine from the feedstock to the gas phase reduces the chlorine content of the char which may reduce the risk of alkali chloride-corrosion in char combustion. However, trace metals catalytically active in the formation of PCDD and PCDF remain in the char, thereby may promote PCDD and PCDF formation during subsequent char combustion for energy recovery; this formation is less extensive than when the feedstock is used.
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| 9. |
- Edo, Mar, et al.
(författare)
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Emissions of toxic pollutants from co-combustion of demolition and construction wood and household waste fuel blends
- 2018
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 203, s. 506-513
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Tidskriftsartikel (refereegranskat)abstract
- Four different types of fuel blends containing demolition and construction wood and household waste were combusted in a small-scale experimental set-up to study the effect of fuel composition on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), chlorobenzenes (PCBzs), chlorophenols (PCPhs) and polycyclic aromatic hydrocarbons (PAHs). Two woody materials, commercial stemwood (ST) and demolition and construction wood (DC) were selected because of the differences in their persistent organic pollutants (POPs), ash and metals content. For household waste, we used a municipal solid waste (MSW) and a refuse-derived fuel (RDF) from MSW with 5-20 wt% and up to 5 wt% food waste content respectively. No clear effect on the formation of pollutants was observed with different food waste content in the fuel blends tested. Combustion of ST-based fuels was very inefficient which led to high PAH emissions (32 +/- 3.8 mg/kg(fuel)). The use of DC clearly increased the total PCDD and PCDF emissions (71 +/- 26 mu g/kg(fuel)) and had a clear effect on the formation of toxic congeners (210 +/- 87 ng WHO2005-TEQ/kg(fuel)). The high PCDD and PCDF emissions from DC-based fuels can be attributed to the presence of material contaminants such as small pieces of metals or plastics as well as timber treated with chromated copper arsenate preservatives and pentachlorophenol in the DC source.
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| 10. |
- Edo, Mar, et al.
(författare)
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The combined effect of plastics and food waste accelerates the thermal decomposition of refuse-derived fuels and fuel blends
- 2016
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 180, s. 424-432
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Tidskriftsartikel (refereegranskat)abstract
- Mechanical treatments such as shredding or extrusion are applied to municipal solid wastes (MSW) to produce refuse-derived fuels (RDF). In this way, a waste fraction (mainly composed by food waste) is removed and the quality of the fuel is improved. In this research, simultaneous thermal analysis (STA) was used to investigate how different mechanical treatments applied to MSW influence the composition and combustion behaviour of fuel blends produced by combining MSW or RDF with wood in different ratios. Shredding and screening resulted in a more efficient mechanical treatment than extrusion to reduce the chlorine content in a fuel, which would improve its quality. This study revealed that when plastics and food waste are combined in the fuel matrix, the thermal decomposition of the fuels are accelerated. The combination of MSW or RDF and woody materials in a fuel blend has a positive impact on its decomposition.
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