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- Andersen, M. S., et al.
(författare)
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To facilitate a fair bioeconomy transition, stronger regional-level linkages are needed
- 2022
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Ingår i: Biofuels Bioproducts & Biorefining-Biofpr. - : Wiley. - 1932-104X .- 1932-1031. ; 16:4, s. 929-941
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Tidskriftsartikel (refereegranskat)abstract
- The great hopes in Brussels that a circular bioeconomy will help bridge the growing divide between urban and rural areas and allow the hinterlands to prosper from 'green growth' are addressed in this article, which reflects on insights from three Nordic case studies of brown, green and blue biomass use at different levels of technology readiness. A closer examination of the forward, backward, fiscal and final demand linkages at regional level from increased biomass utilization, from eastern Finland and northern Sweden to Jutland and North Atlantic islands, suggests that linkages are and will remain relatively weak, predominantly dashing the expectations. As suppliers and exporters of natural resources, disadvantaged regions may all too easily get locked into a 'staples trap', where the value creation evaporates owing in part to the steep start-up costs and the associated boom-and-bust cycles, which place them in a weak position vis-a-vis the resource manufacturers and consumers. To make the prospects of development, employment and prosperity in the hinterlands materialize, measures are needed to strengthen the regional-level economic linkages. Regional-level revolving funds based on benefit-sharing instruments related to natural resources can be used to bolster economic development, as reflected in such schemes present in both China and Canada. We call for further research into whether and how such approaches can be replicated successfully by channeling revenues from biomass cultivation to regional-scale revolving funds, with mandates to strengthen long-term economic linkages and prosperity within the hinterlands. (c) 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd
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- Johansson, Roger
(författare)
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Indirect measurements for control and diagnostics of IC engines
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The combustion process in internal combustion engines determines engine power, fuel consumption, exhaust emissions and combustion noise. Measurement and analysis of in-cylinder pressure plays an important role in the improvement and optimization of engine performance. Measuring pressure directly inside a cylinder is expensive and troublesome since an engine needs modifications to mount a pressure transducer and the harsh environment inside a cylinder will cause a transducer to have a short lifetime. An indirect, non-intrusive method based on external measurements has the potential to offer on-board control and diagnostics of combustion. This thesis focuses on cylinder pressure reconstruction and top dead center localization. For the pressure reconstruction two indirect approaches have been proposed in the literature; 1) engine structure vibration based reconstruction and 2) crankshaft angular speed based reconstruction. The crankshaft speed fluctuation has a high coherence with the cylinder pressure at low frequencies while structure vibrations have a high coherence for higher frequencies. Therefore, a new combined approach based on the two earlier approaches was developed. The combined approach was evaluated with two different methods; inverse filtering and neural networks. The proposed combined approach based on inverse filtering was compared to using either crankshaft speed or structure vibrations. The combined method gave the best results, due to combining the strengths of both methods in different frequency regions. The maximum pressure for the combined method was predicted with an RMS error of less than 5 bars (5%). A further development was to use a radial basis function (RBF) network, which combines a knowledge base with non-linear interpolation. The RBF network was able both to learn the training conditions and generalize this knowledge to untrained running conditions. This method can therefore be used generally, regardless of the actual running condition. For the untrained running conditions the maximum pressure was predicted with an RMS error of less than 3.5 bars (4%). The method based on a RBF network was also the method that gave the best agreement between reconstructed and measured pressure waveforms and was the only method in this thesis found to be able to predict unknown running conditions. Knowledge about piston positions is crucial when injection and ignition timing are set. In this thesis, a method to determine the top dead center from measurement of the crankshaft speed fluctuation was developed and evaluated. The TDC position can typically be determined with an error of less than 0.4 degrees.
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- Johnsson, Roger, et al.
(författare)
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Sensitivity analysis of transfer function estimation in inverse methods
- 2005
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Ingår i: Acta Acoustica united with Acustica. - 1610-1928 .- 1861-9959. ; :Suppl 1, s. S16-
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Tidskriftsartikel (refereegranskat)abstract
- Summary form only given. A complex sound source consists of several partial sound sources that all contribute to the total sound pressure. A method to separate these partial sound sources into separate time histories is based on inverse filtering of reciprocally measured transfer functions. The transfer functions are measured reciprocally between a number of fictitious monopoles on each partial source and measurement points distributed around the sound source. The method is divided into 5 steps: recording of sound pressure signals, measurement of transfer function, calculation of source strength matrix, calculation of filters and filtering of the recorded sound pressure signals. Correct estimations of the transfer functions are critical for inverse methods to work satisfactory. Normally the transfer functions in this case of studies are calculated as H1 because of the noise contribution to the responses. However, it has been suggested that inverse methods could benefit of using H2 instead. The objective of this investigation is to analyze the effect of selecting either H1 or H2 for the calculation of the transfer functions in case of auralization of separated time histories. For the experiments a complex sound source consisting of two separate cylinder heads with valve covers have been used. Each cylinder head with valve cover was treated as a partial source. The two partial sources were excited with two uncorrelated signals that could be controlled individually. By that, listening tests could be used to verify the authenticity of the separated source signals depending of the transfer functions were estimated as H1 or H2
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- Nykänen, Arne, et al.
(författare)
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Assessment of changes in preference ratings of auralized engine sounds caused by changes in frequency resolution of transfer functions
- 2013
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Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 74:12, s. 1343-1353
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Tidskriftsartikel (refereegranskat)abstract
- Auralization facilitates aural examination of contributions from different sound sources, individually and as parts of a context. Auralizations can be created by filtering sounds of perceptually salient sources through binaural transfer functions (BTFs) from source positions to a listening position. When such auralizations are used for product sound design it is essential to know that they are of sufficient quality. A basic requirement is that preference ratings are unaffected by the quality of the auralizations. The objective of this study was to measure changes in preference ratings of auralized engine sounds caused by changes in frequency resolution of used BTFs. Auralizations of engine sounds were created by filtering source sounds through BTFs measured from source positions to a driver’s position inside a truck cabin. The BTFs were altered by lowering the frequency resolution and by smoothing in the frequency domain. Preferences for the auralizations were compared using a modified version of the MUlti Stimulus test with Hidden Reference and Anchor, MUSHRA (ITU-R BS.1534-1). Since the use of a reference is only appropriate when a reference known to be most preferred exists the reference was removed, resulting in a MUlti Stimulus Test with Hidden Anchors (MUSTHA). For assessment of the differences between the auralizations a statistical method commonly used for assessing agreement between methods of clinical measurement was adopted. The lowest frequency resolutions resulting in acceptable agreement between preference ratings of auralizations made with high frequency resolution (1 Hz) BTFs and auralizations made with simplified BTFs were 32 Hz frequency resolution or smoothing with either 1/24 octave bandwidth filters or 63 Hz absolute bandwidth filters.
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| 8. |
- Nykänen, Arne, et al.
(författare)
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Assessment of the change in similarity judgements of auralized engine sounds caused by changes in frequency resolution of transfer functions
- 2011
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Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 72:2-3, s. 115-123
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Tidskriftsartikel (refereegranskat)abstract
- Auralization facilitates aural examination of contributions from different sound sources, individually and as parts of a context. Auralizations can be created by filtering sounds of the perceptually most salient sources through binaural transfer functions (BTFs) from source positions to a listening position. When psychoacoustic analysis is based on auralizations, the auralizations need to give the same impression as real sounds. The objective of this study was to determine the frequency resolution required for auralizations to be perceptually equivalent to recordings made with an artificial head. Auralizations of the contribution of engine sounds to interior sounds of a truck were examined. In listening tests auralizations based on simplified BTFs were compared to artificial head recordings. The BTFs were simplified by lowering the frequency resolution and by smoothing in the frequency domain. Auralizations made through BTFs with a resolution of 4 Hz or higher or smoothed with maximum 1/96 octave moving average filters were perceived as similar to artificial head recordings.
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| 9. |
- Söderholm, Patrik, et al.
(författare)
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Governing the transition to low-carbon futures: A critical survey of energy scenarios for 2050
- 2011
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Ingår i: Futures. - : Elsevier BV. - 0016-3287 .- 1873-6378. ; 43:10, s. 1105-1116
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing scientific consensus that limiting the increase in global average temperature to around 2 C above pre-industrial levels is necessary to avoid unacceptable impact on the climate system. This requires that the developed countries' emissions are radically reduced during the next 40 years. Energy scenario studies provide insights on the societal transitions that might be implied by such low-carbon futures, and in this paper we discuss how a greater attention to different governance and institutional issues can complement future scenario exercises. The analysis is based on a critical review of 20 quantitative and qualitative scenario studies, all of relevance for meeting long-term climate policy objectives. The paper: (a) analyzes some key differences in energy technology mixes and primary energy use patterns across these studies; (b) briefly explores the extent and the nature of the societal challenges and policy responses implied; and (c) discusses a number of important implications for the design and scope of future scenario studies. Our review shows that in previous scenario studies the main attention is typically paid to analyzing the impact of well-defined and uniform policy instruments, while fewer studies factor in the role of institutional change in achieving different energy futures. We therefore point towards a number of strategies of integrating issues of transition governance into future scenario analyses, and argue for a closer synthesis of qualitative and quantitative scenario building. (C) 2011 Elsevier Ltd. All rights reserved.
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| 10. |
- Åhlund, Christer, et al.
(författare)
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Project: Sense Smart City
- 2010
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Annan publikation (populärvet., debatt m.m.)abstract
- Sense Smart City is a Swedish project designed to conduct research, create new business opportunities and sustainably increase ICT research and innovation capability with specific objective to make urban cities/areas "smarter". The project will generate new and better ICT solutions, that instrument urban areas to gather and combine information (energy, traffic, weather, events, activities, needs and oppinions) continously as well as "on-demand". This will enable city environments to become "smarter", as more adaptive and supportive environment, for its inhabitants and visitors - people as well as organisations.
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