| 41. |
- Gustafsson, Marcus, 1987-, et al.
(author)
-
Well-to-wheel greenhouse gas emissions of heavy-duty transports : Influence of electricity carbon intensity
- 2021
-
In: Transportation Research Part D. - : Elsevier. - 1361-9209 .- 1879-2340. ; 93
-
Journal article (peer-reviewed)abstract
- There are several alternatives for how to phase out diesel in heavy-duty transports, thereby reducing the sector’s climate change impact. This paper assesses the well-to-wheel (WTW) greenhouse gas (GHG) emissions of energy carriers for heavy-duty vehicles, analyzing the effect of the carbon intensity of the electricity used in production. The results show that energy carriers with high electricity dependence are not necessarily better than diesel from a WTW perspective. In particular, fuels produced through electrolysis are not well suited in carbon-intense electricity systems. Conversely, waste-based biofuels have low GHG emissions regardless of the electricity system. Battery-electric buses show a large reduction of GHG emissions compared to diesel buses and many other alternatives, while battery-electric trucks have higher GHG emissions than diesel in carbon intense electricity systems. Thus, electrifying transports or switching to renewable fuels will not suffice if the electricity system is not made renewable first.
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| 42. |
- Gustafsson, Robert, et al.
(author)
-
Structure and Characterization of Phosphoglucomutase 5 from Atlantic and Baltic Herring : An Inactive Enzyme with Intact Substrate Binding
- 2020
-
In: Biomolecules. - : MDPI AG. - 2218-273X. ; 10:12
-
Journal article (peer-reviewed)abstract
- Phosphoglucomutase 5 (PGM5) in humans is known as a structural muscle protein without enzymatic activity, but detailed understanding of its function is lacking. PGM5 belongs to the alpha-D-phosphohexomutase family and is closely related to the enzymatically active metabolic enzyme PGM1. In the Atlantic herring, Clupea harengus, PGM5 is one of the genes strongly associated with ecological adaptation to the brackish Baltic Sea. We here present the first crystal structures of PGM5, from the Atlantic and Baltic herring, diering by a single substitution Ala330Val. The structure of PGM5 is overall highly similar to structures of PGM1. The structure of the Baltic herring PGM5 in complex with the substrate glucose-1-phosphate shows conserved substrate binding and active site compared to human PGM1, but both PGM5 variants lack phosphoglucomutase activity under the tested conditions. Structure comparison and sequence analysis of PGM5 and PGM1 from fish and mammals suggest that the lacking enzymatic activity of PGM5 is related to dierences in active-site loops that are important for flipping of the reaction intermediate. The Ala330Val substitution does not alter structure or biophysical properties of PGM5 but, due to its surface-exposed location, could affect interactions with protein-binding partners.
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| 43. |
- Gustavsson, Thorbjörn, et al.
(author)
-
Fuktsäkra byggnader : en nulägesbeskrivning
- 2022
-
Reports (other academic/artistic)abstract
- Boverket ser ett behov av en kunskapssammanställning kring nuläget om fuktsäkra byggnader i Sverige för att ha en så bred och korrekt förståelse som möjligt för vem branschen är, vilka regler som tillämpas, var det finns kunskapscentra och vilka utvecklingsbehov som behöver stödjas för att branschen ska kunna ta större ansvar. De utmaningar som noteras är: Byggsektorn beredskap och förmåga att möta de nya förändrade byggregler som planeras av Boverket.Den stora andelen fuktrelaterade fel och skador som rapporteras i olika utredningar. Kraven kopplat till fuktrelaterade innemiljöproblem är otydliga och ofta svåra att följa upp. Detta kan leda till fuktrelaterade innemiljöproblem som orsakar lidande för de individer som drabbas.Miljö och klimatfrågan ställer krav både på resurseffektivitet och minskad klimatpåverkan samt resiliens och klimatanpassning. Förändrade boendevanor och brukarvanor som ändrar på förutsättningarna i en byggnad. Fragmentering och specialisering med många aktörer med ansvar för sin del endast. Några utvecklingsområden har noterats. Områden där det behövs både forskning och utveckling av teknik, processer och samarbeten: Kvalitetssäkring av nya material, konstruktioner och produktionsmetoderKompetensutveckling och kompetensspridning.Framtagning och tillgängliggörande av kunskap, teknikutveckling. Samsyn behöver utvecklas när det gäller bl.a. uttorkning i betong och i vilken omfattning byggnader behöver skyddas mot fukt under byggproduktionen. Undersökning av utvecklingsmöjligheter behövs för att ta vara på digitaliseringens möjligheter med sensorer, digitala tvillingar, AI m.m. i samband med fuktsäkerhet. Kartläggningen skulle förstärkas med en bredare internationell utblick. Det tycks finnas en del skillnader både i arbetssätt och erfarenheter kring fuktsäkra byggnader.Förhoppningen är att kartläggning av fuktsäkra byggnader ska bidra till kunskapsspridning om bransch, aktörer, teknik, system, konstruktion, kontroller, drift och underhåll samt forskning och fortsatt utvecklingsarbete.
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| 44. |
- Helander, Jakob, et al.
(author)
-
Reflection-Based Source Inversion for Sparse Imaging of Low-Loss Composite Panels
- 2020
-
In: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 68:6, s. 4860-4870
-
Journal article (peer-reviewed)abstract
- This article presents a bistatic reflection-based imaging technique for electromagnetic testing of conductor-backed composite panels, which is based on an inverse formulation of the numerical problem at hand, and technically extends a previously demonstrated transmission-based system. The technique exploits the a priori assumption of pixel-based sparsity and retrieves the final image using data from only a single measurement, thereby removing the necessity of a reference measurement to be conducted. To demonstrate the capability of the technique, retrieved images are presented for a synthetic proof-of-concept device under test and an industrially manufactured composite panel. The presented technique can be considered as the initial model in the development of more complex bistatic imaging systems and has been developed for the purpose of extending the opportunities to conduct reflection-based electromagnetic nondestructive testing on aircraft structural components.
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| 45. |
- Jash, Asmita, et al.
(author)
-
Excitonic Dynamics at the Type-II Polytype Interface of InP Platelets
- 2023
-
In: ACS Photonics. - 2330-4022. ; 10:9, s. 3143-3148
-
Journal article (peer-reviewed)abstract
- Indirect excitons are the focus of intense research due to the opportunity of studying degenerate quantum gases and liquids in an excitonic system. To realize such systems, it is highly advantageous to have as little scattering as possible. A polytype type-II interface is formed between wurtzite and zincblende InP due to the band alignment. Electrons gather on the zincblende and holes on the wurtzite side of the interface. Therefore, electrons and holes that are spatially separated by the interface form indirect excitons with aligned dipoles. This polytype type-II interface is perfectly flat, which limits scattering. Here we report that repulsive interaction between the indirect excitons is the driving force behind the long-range transport of indirect excitons along the interface at high exciton densities. This is indicative of less scattering than in conventional type-II heterostructures. The spatial separation of the charge carriers across the interface leads to a low recombination rate of the indirect excitons since the overlap of the electron-hole wavefunction at the interface is small. Emission from the long-lived indirect excitons can be detected even after 40 μs. Our studies have been performed by using spatially and temporally resolved photoluminescence at the low temperature.
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| 46. |
- Jash, Asmita, et al.
(author)
-
Time-resolved photoluminescence studies of single interface wurtzite/zincblende heterostructured InP nanowires
- 2022
-
In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 120:11
-
Journal article (peer-reviewed)abstract
- The interface between wurtzite and zinc blende InP has been identified as type-II, where electrons gather on the zinc blende side and holes on the wurtzite side of the interface. The photoluminescence resulting from recombination across the interface is expected to be long-lived and to exhibit non-exponential decay of emission intensity after pulsed excitation. We verify this prediction using time-resolved photoluminescence spectroscopy on nanowires containing a single heterostructure between a single segment of wurtzite and zinc blende. We find that a significant intensity of type-II emission remains even more than 30 ns after excitation. The decay of the emission intensity is also non-exponential and considerably longer than the exponential decay of the wurtzite InP segment (260 ps). Our results are consistent with the expected photoluminescence characteristics of a type-II interface between the two polytypes. We also find that the lifetime becomes shorter if we create an electron gas at the interface by n-type doping the entire wurtzite segment of the nanowire. This is expected since there are many electrons that a given hole can recombine with, in contrast to the undoped case.
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| 47. |
- Jelinek, Lukas, et al.
(author)
-
Fundamental bounds on the performance of monochromatic passive cloaks
- 2021
-
In: Optics Express. - 1094-4087. ; 29:15
-
Journal article (peer-reviewed)abstract
- Fundamental bounds on the performance of monochromatic scattering-cancellation and field-zeroing cloaks made of prescribed linear passive materials occupying a predefined design region are formulated by projecting field quantities onto a sub-sectional basis and applying quadratically constrained quadratic programming. Formulations are numerically tested revealing key physical trends as well as advantages and disadvantages between the two classes of cloaks. Results show that the use of low-loss materials with high dielectric contrast affords the highest potential for effective cloaking.
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| 48. |
- Jelinek, Lukas, et al.
(author)
-
Maximum Radiation Efficiency of Implanted Antennas Employing a Novel Hybrid Method
- 2021
-
In: 2021 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, APS/URSI 2021 - Proceedings. - 9781728146706 ; , s. 1339-1340
-
Conference paper (peer-reviewed)abstract
- A hybrid combining T-matrix method and electric field integral equation is used to formulate fundamental bounds on radiation efficiency of an implanted antenna. Resulting quadratic optimization problem is solved using a dual formulation. The results present the versatility of the described computational scheme and show the optimal current densities that are the least impaired by dissipation in the tissue.
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| 49. |
- Johannesson, Mikael, 1959-, et al.
(author)
-
Redovisning av regeringsuppdrag om mikroplast från vägtrafiken
- 2021
-
Reports (other academic/artistic)abstract
- Denna rapport är en redovisning av det regeringsuppdrag VTI fick i december 2017 om att ta fram och sprida kunskap om mikroplast från vägtrafiken och som löpte fram till den 1 juni 2021. Uppdraget omfattade en budget på totalt 20 Mkr. Anledningen till uppdraget var bl.a. att kunskapen om mikroplast från vägtrafiken är mycket begränsad samtidigt som däck- och vägslitagepartiklar från vägtrafiken är en stor källa. Uppdraget var ett led i regeringens arbete att nationellt och internationellt genomföra insatser för att minska problemen med plast i miljön. Rapporten är strukturerad utifrån den kunskap som specifikt efterfrågas i uppdraget, som t.ex. kunskap om hur partiklarna sprids och vad man kan göra åt det, samt vad regeringen önskar att VTI ska göra, som t.ex. skriva vetenskapliga artiklar, samverka med myndigheter och sprida kunskap.Denna rapport är en sammanfattning av de aktiviteter som genomförts och de resultat som kommit fram inom ramen för uppdraget. Kunskapen om mikroplast från däck- och vägslitagepartiklar har från en låg nivå ökat snabbt under senare år genom forskning som bedrivits inom och utanför regerings-uppdraget. Det gäller t.ex. kunskap om beredning och analys av prover, däckpartiklars fysiska och kemiska egenskaper, däck- och vägslitagepartiklars förekomst i väg- och gatumiljö, deras potentiella spridningsvägar, vilka potentiella styrmedel och åtgärder som finns.
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| 50. |
- Jonasson, Mats, 1969, et al.
(author)
-
Simultaneous vehicle dynamics state estimation using pitch-rate sensor
- 2020
-
Patent (other academic/artistic)abstract
- There is provided a method for estimating friction between a tire of a vehicle and a road surface, the method comprising acquiring, a front wheel axle torque, a rear wheel axle torque, a vehicle longitudinal acceleration, a vehicle pitch rate and wheel rotational velocities. The method further comprises determining a front wheel normal force and a rear wheel normal force, based on a center of gravity of the vehicle and the longitudinal acceleration; determining a longitudinal tire stiffness, jointly determining a vehicle longitudinal velocity, based on the wheel rotational velocities and vehicle longitudinal acceleration, and a vehicle pitch angle relative to the horizontal plane based on the vehicle pitch rate; and determining a friction coefficient between tires and ground based on the front and rear wheel axle torque, the front wheel normal force and the joint estimation of pitch angle and vehicle longitudinal velocity. There is also provided a system for performing the described method.
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