| 1. |
- Dian, Eszter, et al.
(författare)
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Validation of Detailed Geant4 Model for Thermal Neutron Scattering using the Results of Multi-Grid Detector Prototype Test at CNCS at SNS
- 2017
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Ingår i: 2017 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC). - : IEEE. - 9781538622827
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Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) aspires to be the worlds leading neutron source of the upcoming decades, and sets the scope on replacing He-3 tube detectors where it is reasonably achievable. The Multi-Grid detector, an Ar/CO2-filled proportional chamber based on solid (B4C)-B-10 converter, is the most potent replacement technology for chopper spectroscopy. This study reproduces in a detailed Geant4 geometry of a neutron scattering instrument the data from the Multi-Grid demonstrator detector, that has been tested for a 1 year period, installed side-by-side to the He-3 tubes at the CNCS instrument at SNS. For the further understanding of the background of the detector, Monte-Carlo simulations were performed, with the ESS Coding Framework, using a Geant4 version extended with NXSG4 and NCrystal. A detailed and realistic model of the prototype was built and was validated via comparison against measured data. With this model, different sources of neutron scattering were determined and studied separately, providing a better understanding of the scattered neutron background. Due to these capabilities the model will be used in the further optimization of the detector, especially for the background reduction via shielding, which will lead to instruments with better signal-to-background ratio by design.
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| 2. |
- Kanaki, Kalliopi, et al.
(författare)
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Simulation tools for detector and instrument design
- 2018
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Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 551, s. 386-389
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Tidskriftsartikel (refereegranskat)abstract
- The high performance requirements at the European Spallation Source have been driving the technological advances on the neutron detector front. Now more than ever is it important to optimize the design of detectors and instruments, to fully exploit the ESS source brilliance. Most of the simulation tools the neutron scattering community has at their disposal target the instrument optimization until the sample position, with little focus on detectors. The ESS Detector Group has extended the capabilities of existing detector simulation tools to bridge this gap. An extensive software framework has been developed, enabling efficient and collaborative developments of required simulations and analyses – based on the use of the Geant4 Monte Carlo toolkit, but with extended physics capabilities where relevant (like for Bragg diffraction of thermal neutrons in crystals). Furthermore, the MCPL (Monte Carlo Particle Lists) particle data exchange file format, currently supported for the primary Monte Carlo tools of the community (McStas, Geant4 and MCNP), facilitates the integration of detector simulations with existing simulations of instruments using these software packages. These means offer a powerful set of tools to tailor the detector and instrument design to the instrument application.
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| 3. |
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| 4. |
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| 5. |
- Forsström, Stefan, 1984-, et al.
(författare)
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A Plain Low Threshold IoT Platform for Enabling New IoT Products from SMEs
- 2020
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Ingår i: 2020 IEEE International Workshop on Metrology for Industry 4.0 & IoT. - : IEEE. - 9781728148922 ; , s. 390-394
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Konferensbidrag (refereegranskat)abstract
- Many small and medium enterprises have existing products that they want to innovate on and move into the new era of Internet of Things. Because of this, we have developed a plain Internet of Things platform aimed towards businesses who wants to try out these new systems but does not have the resources to develop or maintain a full platform from the traditional providers. We have developed an open source solution that can be run on cheap off the shelf hardware and employs today's de facto standards for Internet of Things systems. Our solution also provides adequate functionality for an initial effort and innovation, including taking security and privacy concerns into consideration. We have also evaluated our implementation in terms of scale, which shows that the system scales well in scenarios with up to 50 sensor values per second. Which should be enough for a small business first effort to try out their products as an Internet of Things service.
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| 6. |
- Gulliksson, Mårten, et al.
(författare)
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Perturbation bounds for constrained and weighted least squares problems
- 2002
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Ingår i: Linear Algebra and Its Applications. - 0024-3795. ; 349, s. 221-232
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Tidskriftsartikel (refereegranskat)abstract
- We derive perturbation bounds for the constrained and weighted linear least squares (LS) problems. Both the full rank and rank-deficient cases are considered. The analysis generalizes some results of earlier works.
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| 7. |
- Hoogendoorn, Billy W., et al.
(författare)
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Formation of Different Zinc Oxide Crystal Morphologies Using Cellulose as Nucleation Agent in the Waste Valorization and Recycling of Zn-Ion Batteries
- 2023
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Ingår i: Rare Metal Technology 2023. - Cham : Springer.
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Konferensbidrag (refereegranskat)abstract
- The formation of zinc oxide particles of different hierarchical morphologies was investigated. By performing elemental analysis on samples extracted from the supernatant solution during precipitations yielding two distinctly different morphologies, the consumption of zinc ions was used to follow the liquid-to-solid phase formation. While a rapid Zn-ion consumption was synonymous with the formation of predominantly oxygen terminated flower-shaped ZnO-particles, with half of the zinc ions being precipitated during the first minute, less than 10% of the zinc ions were converted to sea urchin-shaped ZnO-particles (with mixed terminations) after 1 min of the reaction. The unique ZnO-particle morphologies may therefore be related to the precipitation rates, which can be further explored as a tool for understanding how ZnO-particles with differently facetted surfaces form. Interestingly, the different formation rates remained with identical patterns when 0.5 g/L cellulose (0.005 wt%) was added to the reactions as nucleating agent for improved yields. The controlled formation of specific functional ZnO-particle surfaces is an important method for recycling inexpensive zinc waste from batteries to high value materials useful in a variety of catalytic applications.
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| 8. |
- Hu, Xiao, et al.
(författare)
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Product gas biomethanation with inoculum enrichment and grinding
- 2024
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Ingår i: Biomass Conversion and Biorefinery. - : Springer Nature. - 2190-6815 .- 2190-6823. ; 14:12, s. 12993-13004
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Tidskriftsartikel (refereegranskat)abstract
- The use of cheap product gas from biomass air gasification to produce methane via anaerobic digestion is a novel and potential pathway for the large-scale production of biomass-based substitute natural gas (BioSNG). In this experimental work, the product gas biomethanation (PGB) was studied with respect to the biosludge enrichment and inoculum partial grinding as well as the mesophilic and thermophilic conditions. The results show that the biosludge enrichment can effectively stop methanogenesis inhibition from the product gas, particularly CO, thus increase the biomethanation reaction rate and shorten the reaction start-up time. The inoculum partial grinding treatment can clearly change the microorganism composition and effectively reduce the diversity of microorganisms in the mixed bacterium system for the mesophilic biomethanation, thereby improving the product gas biomethanation efficiency, which is limited for the thermophilic biomethanation.
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| 9. |
- Jiang, Bingyi, et al.
(författare)
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A novel approach to enhance CO biomethanation by semi-disaggregation of anaerobic granular sludge
- 2023
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 276
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Tidskriftsartikel (refereegranskat)abstract
- The syngas produced from biomass gasification is a great potential energy resource, which can well be utilized to produce biomass-based substitute natural gas (BioSNG) via syngas biomethanation. CO biomethanation is one of the key issues in the biomethanation process and was studied experimentally in this work with respect to the effect of anaerobic granular sludge semi-disaggregation. The results show 1.07 times higher averaged CH4 production rate with the semi-disaggregated granular sludge than the whole granular sludge at 35 °C, and 1.69 times higher at 55 °C. The main mechanisms behind the enhanced CH4 production rate, especially under the thermophilic condition, are the improvement of microbial interspecific syntrophic association caused by the higher electron and substrate transfer rate, and more active cell growth and metabolism as reflected in higher abundance of functional genes and enzymes and less useless extracellular polymeric substances. The CO biomethanation enhancement occurs in the conversion of the substrate to the intermediate products. The semi-disaggregation of anaerobic granular sludge or similar way to strengthen interspecific association is an effective approach to improve the ability and tolerance of microbial cultures under the CO atmosphere. This technique can well be applied for the energy conversion from the CO-rich gas substrates into BioSNG via CO biomethanation under the thermophilic condition, or for the production of intermediates as fuels/chemicals under the mesophilic condition.
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| 10. |
- Jiang, Bingyi, et al.
(författare)
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Identification of the biomethanation pathways during biological CO2 fixation with exogenous H2 addition
- 2022
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Ingår i: Fuel processing technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- Power-to-gas allows conversion of surplus electricity to methane when CO2 is available, which becomes an important technology for carbon capture, utilization and sequestration, as well as for increasing the flexibility of electricity production from renewable energy resources such as wind and solar energy. H2/CO2 biomethanation is a potentially promising alternative to the conversion of H2/CO2 to methane without limitation of variable hydrogen production. To identify mixed culture-based metabolic pathways of H2/CO2 under the mesophilic (35 °C) and thermophilic (55 °C) conditions, two specific inhibitors, 2-bromoethane sulfonate (BES) and vancomycin were employed in this experimental study. The combination of hydrogenotrophic and homoacetogenesis-acetoclastic methanogenesis makes up the pathway for the mesophilic cultivated microbial consortia. 16S rRNA gene analysis indicates that abundant Bacteria, Methanobacterium and Methanosaeta play important role in the conversion. Further analysis shows close collaboration between microorganisms by the formation of microbial clustering and the production of humic acids. The detailed metabolic mechanisms further confirm a diverse biomethanation network under the mesophilic condition. While under the thermophilic condition, the H2/CO2 biomethanation is fully dominated by the direct hydrogenotrophic methanogenesis mainly with Methanothermobacter, which is straightforward but more efficient.
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