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The work presented in this thesis is based on time-resolved x-ray diffraction studies of InSb (111) samples. The experiments were carried out using a pump-probe configuration using short laser pulses as the pump and x-rays as the probe. Laser excitation leads to the formation of a strain pulse that propagates through the sample. The strain pulse gives rise to coherent longitudinal, acoustic phonon
Popular Abstract in Swedish Den rykande startpistolen eller Konsten att ta tid på en flygande elektron Flygande elektroner kan berätta mycket om hur världen sitter ihop. Elektroner som lämnar ytan av något material avslöjar både vilka atomer som finns i materialet och hur de kemiska bindingarna ser ut. Allt detta är nödvändigt att förstå när man vill utveckla nya material – till exempel för kretTime-of-flight (TOF) techniques for energy analysis have been common in electron spectroscopy for many decades. TOF-based electron spectrometers benefit from higher transmission and information rate compared to their main competitor: the hemispherical analyser; the drawback being their lower energy resolution. However, the advent of angle-resolved TOF spectrometers for electron energy analysis cha
Off-grid solar products play an essential role in increasing and improving rural energy access, thereby reducing poverty and mitigating climate change. Experiencing fast market growth in Central and Southern Asia and Sub-Saharan Africa, off-grid solar products will represent 50% of the newly established electricity connections in the world between 2017 and 2030. Despite such benefits and market su
Sammanfattning Under 1960-talet kunde vetenskapsmän konstatera att en generell uppvärmning av atmosfären resulterade i klimatförändringar. En av källorna till den globala uppvärmningen var och är fortfarande den höga koncentrationen av växthusgaser i atmosfären som uppstår genom mänsklig aktivitet vid förbränning av fossila bränslen. Trots den vetskapen dröjde det en bit in på 2000-talet innan kliSummary In the 1960’s scientists discovered that general heating of the atmosphere or global warming results in climate change. One of the reasons behind global warming is the high concentration of green house gases in the atmosphere, which is a bi-product of fossil fuel combustion caused by human activity. Climate change did not become a European Union priority before the 21st century when the c
Öresundskraft – A bright internship NGEA51, January 20 – March 20 2020 Isabell Plars At the start of 2020, I did an internship at Öresundskraft in Helsingborg. Öresundskraft is an energy company owned by the city of Helsingborg. The purpose of Öresundskraft is to supply the citizens of Helsingborg with energy in the form of both electricity and heat. Öresundskraft is also involved in a lot of inno
https://www.nateko.lu.se/sv/sites/nateko.lu.se.sv/files/oresundskraft_2020.pdf - 2026-07-05
This thesis evaluates the ability of three hand-calculation models for estimating overpressure from hydrogen vapour cloud explosions. The models were the TNT, TNO and OHVE models. The aim was to assess their performance in realistic release environments and identify their strengths and limitations. Model predictions were validated against experimental data from three experimental setups: a refuell
Professor emeritus Contact details Email: villy [dot] sundstrom [at] chem [dot] lu [dot] seOrganisation Chemical Physics Service point: 1 WebpageVilly Sundströms profile in Lund University research portalOther affiliations Member of Strategic Research Area NanoLund: Centre for Nanoscience Profile area member Lund Laser Centre, LLC Profile area member LTH Profile Area: Nanoscience and Semiconductor
https://www.chemphys.lu.se/villy-sundstrom - 2026-07-04
Enzymes that require a redox-active amino acid for catalysis or function have emerged as a distinct class of proteins. For the tyrosine-based radical enzymes, we show that the spin-density distribution in the radical follows an odd alternate pattern that is invariant to within 10% across the class. General properties of the radical enzymes are summarized from which we conclude that their essential
The steel and chemical production industries are the largest industrial emitters of greenhouse gases in the European Union, together accounting for half of the EU’s industrial greenhouse gas (GHG) emissions. A promising strategy for achieving deep GHG emissions reductions is the electrification of these two industries, which would depend on the rapid expansion of renewable electricity supply. Such
This study presents a novel approach using Gaussian process model predictive control (MPC) to stabilize the output voltage of a polymer electrolyte fuel cell (PEFC) by regulating hydrogen and airflow rates. Two Gaussian process models capture PEFC dynamics, accounting for constraints like hydrogen pressure and input change rates to reduce predictive control errors. The performance of the physical
This paper presents a study of the pH dependence of the activity and stability of a set of family 11 xylanases for which X-ray structures are available, using the PROPKA approach. The xylanases are traditionally divided into basic and acidic xylanases, depending on whether the catalytic acid is hydrogen bonded to an Asn or Asp residue. Using X-ray structures, the predicted pH values of optimal act
The catalytic copper site in nitrite reductase contains a Cu2+ ion bound to three histidine (His) ligands and a solvent molecule. Sites from various sources show a conspicuous variation in the structure. In some proteins, it is close to tetrahedral (even more so than are blue copper proteins), whereas in other proteins, it has a structure more similar to that expected for a type 2 copper site. We
Ammonia (NH3) has been identified as a potential hydrogen-carrier fuel with no carbon emissions. Non-intrusive in-situ NH3 diagnostic technique is of great interest. In this work, femtosecond two-photon laser-induced fluorescence (fs-TPLIF) was demonstrated in NH3/N2 mixtures to achieve NH3 measurements. A femtosecond laser at 305 nm was used for two-photon excitation of NH3 to its excited state (
Growing concerns about climate change and depleting fossil feedstocks are driving a shift within the chemical industry from energy-intensive processes to more environmentally sound and sustainable processing using renewable feedstocks. One such process is the utilization of lipases for the chemo-enzymatic epoxidation of vegetable oils and fatty acids. The lipase mediated route for production of fa
We present the results of the commissioning of a 28-pole 2 T Hybrid Wiggler at the electron storage ring of the Brazilian Synchrotron Light National Laboratory (LNLS). The wiggler will be used mainly for protein crystallography and was optimized for the production of 12 keV photons. We describe the effects of the insertion device on the storage ring lattice, such as the correction of the linear tu
The plasma–surface interface has sparked interest due to its potential of creating alternative reaction pathways not available in typical gas–surface reactions. Currently, there are a limited number of in situ studies investigating the plasma–surface interface, restricting the development of its application. Here, we report the use of in situ ambient pressure X-ray photoelectron spectroscopy in ta
INTRODUCTIONBoreal forests are crucial for mitigating global climate change by capturing and storing large amounts of atmospheric carbon dioxide. However, previously unmanaged primary boreal forests are being rapidly transformed to managed secondary forests to meet the rising global demand for materials and energy. Understanding the effects of boreal primary to managed secondary forest transformat
