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- 2019
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Tidskriftsartikel (refereegranskat)
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- Aspers, Patrik, et al.
(författare)
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Market Fashioning
- 2020
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Ingår i: Theory and society. - : Springer Science and Business Media LLC. - 0304-2421 .- 1573-7853. ; 49, s. 417-438
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Tidskriftsartikel (refereegranskat)abstract
- How do markets come about? This article offers a first systematic analysis of three different ideal types of market fashioning: mutual adjustment, organization, and fields. Although aspects of these are identifiable in most empirical markets, these three ideal types provide analytic tools for students of real markets and marketplaces. After going through this comprehensive literature, it is argued that mutual adjustment, which refers to non-planned processes, is affinity with markets in which products are differentiated, for example, producer markets. Organization refers to process driven by attempts to decide for others and shows affinity with markets for standardized and homogenous products, for example, stock exchanges. Organization also accounts for the making of marketplaces. The broader notion of fields does not refer to any specific process, but accounts for the context of market fashioning and its respective power struggles.
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| 4. |
- Aspers, Patrik, et al.
(författare)
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Wie entstehen Märkte? Ein Vergleich idealtypischer Erklärungsansätze in Ökonomie und Wirtschaftssoziologie : [How do markets emerge? A comparison of ideal-typical explanations in economics and economic sociology]
- 2022
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Ingår i: Berliner Journal für Soziologie. - : Springer Science and Business Media LLC. - 0863-1808 .- 1862-2593. ; 32:4, s. 533-562
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Tidskriftsartikel (refereegranskat)abstract
- In Theorien des Ökonomischen wird die Frage nach der Entstehung von Märkten vergleichsweise randständig behandelt. Wie der Artikel zeigt, lassen sich die dominanten Erklärungsmuster in drei Gruppen zusammenfassen, die jeweils einem idealtypischen Leitkonzept der Marktgestaltung folgen: wechselseitige Anpassung, Organisation und soziale Felder. Während Theorien der wechselseitigen Anpassung von der quasi-natürlichen Genese von Märkten im Prozess reziproker Anerkennungsprozesse der Marktteilnehmer ausgehen, fokussieren Organisationstheorien die bewusste Gestaltung relevanter Institutionen, insbesondere, aber nicht nur durch den Staat. Die durch Bourdieu und Fligstein inspirierte Theorie sozialer Felder nimmt die außerökonomische Einbettung von Marktentstehungsprozessen in den Blick, liefert jedoch keinen genuinen Beitrag zur Interpretation solcher Prozesse im engeren Sinne. Der eingehende analytische Vergleich der jeweiligen Literatur zeigt die Anwendbarkeit der jeweiligen Erklärungsmuster. So betrifft das Phänomen der wechselseitigen Anpassung vor allem ungeplante Prozesse und Märkte mit starker Produktdifferenzierung, das Phänomen der Organisation hingegen vor allem „gerahmte“ Märkte für standardisierte Produkte sowie Wertpapiermärkte. Theorien sozialer Felder adressieren übergreifend den sozialen Kontext und die Machtkämpfe, in denen Märkte als politisch-kulturelle Strukturen ausgehandelt werden. Auf Basis dieser Beobachtung plädiert der Beitrag für eine integrierende Perspektive, die die Vorteile der jeweiligen Ansätze ohne Reduktion auf ein Paradigma in sich vereint.
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| 5. |
- Bengtsson, Alexander, et al.
(författare)
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Characterization and modeling of acousto-optic signal strengths in highly scattering media
- 2019
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Ingår i: Biomedical Optics Express. - 2156-7085. ; 10:11, s. 5565-5584
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasound optical tomography (UOT) is an imaging technique based on the acousto-optic effect that can perform optical imaging with ultrasound resolution inside turbid media, and is thus interesting for biomedical applications, e.g. for assessing tissue blood oxygenation. In this paper, we present near background free measurements of UOT signal strengths using slow light filter signal detection. We carefully analyze each part of our experimental setup and match measured signal strengths with calculations based on diffusion theory. This agreement between experiment and theory allows us to assert the deep tissue imaging potential of similar to 5 cm for UOT of real human tissues predicted by previous theoretical studies [Biomed. Opt. Express 8, 4523 (2017)] with greater confidence, and indicate that future theoretical analysis of optimized UOT systems can be expected to be reliable. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
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| 6. |
- Bengtsson, Alexander, et al.
(författare)
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Comparison of contrast-to-noise ratios of different detection methods in ultrasound optical tomography
- 2022
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Ingår i: Biomedical Optics Express. - 2156-7085. ; 13:9, s. 4834-4850
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasound optical tomography (UOT) is a hybrid imaging modality based on interaction between ultrasound and light, with a potential to extend optical imaging capabilities in biological tissues to depths of several centimeters. Several methods have been developed to detect the UOT signal. To better understand their potential for deep tissue imaging, we present a theoretical contrast-to-noise comparison between the spectral hole burning, single-shot off-axis holography, speckle contrast, and photorefractive detection methods for UOT. Our results indicate that spectral hole burning filters have the potential to reach the largest imaging depths. We find that digital off-axis holography and photorefractive detection can have good contrast-to-noise ratio at significant depths. The speckle contrast method has a smaller penetration depth comparatively.
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| 7. |
- Bengtsson, Alexander
(författare)
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Material and technique development for ultrasound optical tomography using spectral hole burning filters
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The molecular sensitivity provided by optical photons has potential advantages in medical diagnostics, for example, in distinguishing healthy from cancerous tissue. However, scattering resulting from inhomogeneities in the refractive index of tissues prevents spatially resolved optical measurements in biological material, except at very shallow depths. This thesis presents research on a medical imaging technique called ultrasound optical tomography (UOT), which overcomes the limit on resolution resulting from scattering by combining photons and ultrasound. Photons are locally frequency shifted (tagged) by ultrasonic waves inside the tissue. Optical contrast can be obtained with ultrasonic spatial resolution by detecting these tagged photons. In this work, the tagged photons were detected using narrowband optical passband filters created in rare-earth-ion-doped crystals using spectral hole burning techniques. The thesis presents UOT measurements using Pr3+:Y2SiO5 filters operating at 606 nm, which characterize the signal strength under various well-controlled experimental conditions. Improved understanding of the performance of an optimized UOT set-up based on spectral hole burning was obtained by fitting experimental data with theoretical models, indicating that imaging depths of several centimetres should be possible in biological tissues. A theoretical comparison of the many UOT methods described in the literature is presented. The findings indicate that spectral hole burning filters may have better contrast-to-noise scaling, and thus potentially greater imaging depths, than other UOT methods such as digital off-axis holography, photorefractive holography, and speckle contrast imaging. A major challenge for spectral-hole-burning filter-based UOT to become useful for in vivo applications, is to identify and develop crystals capable of supporting the required high-contrast filters at wavelengths within the optical window for tissue (~650-950 nm). Experimental values of the filter contrast obtained in UOT measurements in this wavelength range have so far been limited to 14 dB. Based on spectroscopic measurements, Tm3+:LaF3 is proposed as a candidate for UOT filtering at 690 and 797 nm. Measurements show that a filter contrast above 50 dB is possible at the 690 nm transition for a collimated laser beam. The high filter contrast of Tm3+:LaF3 is expected to be important for the future development of UOT using spectral hole burning filters.
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| 8. |
- Bengtsson, Jenny, et al.
(författare)
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Chemical Recycling of a Textile Blend from Polyester and Viscose, Part II : Mechanism and Reactivity during Alkaline Hydrolysis of Textile Polyester
- 2022
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 14:11
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Tidskriftsartikel (refereegranskat)abstract
- Chemical recycling of textiles holds the potential to yield materials of equal quality and value as products from virgin feedstock. Selective depolymerization of textile polyester (PET) from regenerated cellulose/PET blends, by means of alkaline hydrolysis, renders the monomers of PET while cellulose remains in fiber form. Here, we present the mechanism and reactivity of textile PET during alkaline hydrolysis. Part I of this article series focuses on the cellulose part and a possible industrialization of such a process. The kinetics and reaction mechanism for alkaline hydrolysis of polyester packaging materials or virgin bulk polyester are well described in the scientific literature; however, information on depolymerization of PET from textiles is sparse. We find that the reaction rate of hydrolysis is not affected by disintegrating the fabric to increase its surface area. We ascribe this to the yarn structure, where texturing and a low density assures a high accessibility even without disintegration. The reaction, similar to bulk polyester, is shown to be surface specific and proceeds via endwise peeling. Finally, we show that the reaction product terephthalic acid is pure and obtained in high yields. © 2022 by the authors.
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| 9. |
- Bengtsson, Jenny, et al.
(författare)
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Impact of non-solvents in the tetrabutylammonium acetate : dimethyl sulfoxide-cellulose system
- 2016
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Ingår i: The 7th Workshop on cellulose, regenerated cellulose and cellulose derivatives. ; , s. 19-22
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This work examines the potential of tetrabutylammonium acetate: dimethyl sulfoxide (TBAAc:DMSO) as a solvent used in a process for producing man-made cellulose fibers. The tolerance towards nonsolvents is an important step to evaluate the recyclability of the solvent. TBAAc:DMSO was in this work further confirmed to be an efficient solvent for cellulose. Non-solvent tolerance depended on cellulose concentration, TBAAc:DMSO ratio and type of non-solvent. There was no significant change in mechanical properties for filaments regenerated from solutions containing 2 wt% non-solvent compared to those spun from virgin solvent. With 4 wt% ethanol present in solution very brittle filaments were produced, not suitable for use as textile fibers.
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