| 1. |
- Boix, Virginia
(author)
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Graphene: Applications in Surface Science Studies
- 2022
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Doctoral thesis (other academic/artistic)abstract
- This thesis addresses how graphene can be a valuable asset for surface science studies. Using a combination of X- ray photoelectron spectroscopy, scanning tunneling microscopy, and low-energy electron diffraction, we take advantage of graphene’s sensitivity to changes in its chemical environment to obtain an atomic scale understanding of different reactions occurring above and below the film.As a substrate, graphene provides an inert base for studying growth mechanisms. Specifically, we use it to investigate the electron-induced dissociation of borazine, a common precursor for Boron Nitride deposition. Thanks to the inert character of graphene, we can discern the dissociation due to the interaction with the electron beam from any surface- induced dissociation processes. Moreover, graphene can be used as an adsorption template for studying reactions between adsorbates and gas phase molecules. Using hydrogen adsorbates, we analyze the stability of different H- structures under mbar pressures of oxygen. We show that graphene acts as a catalyst for water formation by providing the required adsorption configuration that promotes the reaction. This finding paves the way for future research using graphene as an adsorption template for fundamental catalysis studies.Graphene can also be employed as a confining agent to study undercover reactions, a trending topic in the catalysis field due to the reported higher performance of catalysts when placed in confined environments. We use graphene to investigate copper oxidation undercover, revealing that its presence stabilizes a Cu2O phase undercover, delaying the evolution toward complete oxidation (CuO). Graphene is also an ideal model system for studying more fundamental aspects of undercover reactions, such as the coexistence of different molecules undercover or their intercalation kinetics. Specifically, we use graphene to investigate the coexistence of hydrogen and CO with already intercalated oxygen while following the intercalation process in situ with APXPS.Altogether this thesis provides several examples of how graphene can be integrated into surface science studies and paves the way for its implementation in the surface science field.
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| 2. |
- Johnson, Lars, 1983-, et al.
(author)
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Spinodal Decomposition of Ti0.33Al0.67N Thin Films Studied by Atom Probe Tomography
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Other publication (other academic/artistic)abstract
- The decomposition of Ti0.33Al0.67N thin films deposited by cathodic arc evaporation have been studied by atom probe tomography. As-deposited films were found to deviate slightly from a random solid solution, and so be in the earliest stage of decomposition. After annealing at 900 °C for 2 h the films exhibited a spinodally decomposed nanostructure, in an intermediate stage. N was found to preferentially segregate to the Al-rich domains in the annealed sample, causing the TiN-domains to be understoichiometric. A possible Kirkendall effect was detected for the annealed sample, with a modulation of the local stoichiometry by 1-2 at. % along the decomposition gradient.
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| 3. |
- Mevada, Dinesh, et al.
(author)
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Experimental performance evaluation of solar still with zig-zag shape air cooled condenser: An energy-exergy analysis approach
- 2023
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In: Energy Reports. - : ELSEVIER. - 2352-4847. ; 10, s. 1198-1210
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Journal article (peer-reviewed)abstract
- In the present experimental effort is made to increase the performance of a solar still (SS) by including a novel design of a zig-zag-shaped air-cooled condenser (ZZACC) and cuprous oxide (CuO) as a nanomaterial. Research work is conducted in the climatic conditions of Gandhinagar, Gujarat, India, from September to November 2020. A comparison was made to assess the performance of a conventional solar still (CSS) and a solar still equipped with a zig-zag shape air-cooled condenser (SSWZZACC) with CuO. The experiments findings showed that adding CuO to SSWZZACC increases the distillate production by 46.83% and the daily energy efficiency by 45.98%, respectively, compared to CSS. Also, SSWZZACC demonstrates a better efficiency of exergy and latent heat of vaporization than CSS because CuO causes an increase in the evaporative heat transfer coefficient of water. In life cycle cost analysis study discovered that SSWZZACC has a 27.77% lower cost per litre of water (CPL) than CSS. The obtained maximum energy and exergy efficiency values for CSS and SSWZZACC were 2.36% & 25.75% and 3.9% & 37.59%, respectively. In economic and environmental aspects, it was found that SSWZZACC with CuO showed a cost-effective desalination unit and was highly effective from a carbon credit point of view (CCP) by CO2 mitigation.& COPY; 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 4. |
- Punzi, Marisa
(author)
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Treatment of Textile Wastewater by Combining Biological Processes and Advanced Oxidation
- 2015
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Doctoral thesis (other academic/artistic)abstract
- Treatment of textile wastewater is challenging because the water contains toxic compounds that have low biodegradability. Dyes, detergents, surfactants, biocides and more are used to improve the textile process and to make the clothes resistant to physical, chemical and biological agents. New technologies have been developed in the last decades and in particular Advanced Oxidation Processes (AOPs) have shown considerable potential for treatment of industrial effluents. These processes however are expensive and full scale applications are still scarce. In addition, the complex oxidation chemistry transforms the pollutants into a very large number of degradation intermediates which may be even more toxic than the original compounds. This thesis presents a novel treatment approach where two AOPs, photo-Fenton oxidation and ozonation, are used after an anaerobic biofilm process for treatment of textile wastewater, azo dyes degradation and removal of toxicity. The biological treatment cleaves the azo bonds of the dyes and consumes the biodegradable compounds whereas the following advanced oxidation degrades the aromatic amines and other by-products that are recalcitrant to biological degradation. The approach that includes photo-Fenton oxidation resulted in higher reduction of chemical oxygen demand (COD) than that with ozonation when treating real textile wastewater. The latter however resulted in higher reduction of toxicity towards the bacteria Vibrio fischeri and the shrimp Artemia salina. Mutagenic effects were detected in the untreated and biologically treated effluent, but not after photo-Fenton oxidation and ozonation. Environmental impact and costs of the two treatment strategies, at the operating conditions used in this study, are high compared with the full-scale biological process used in the Netherlands, where the wastewater is actually treated. Substitution of artificial light with sunlight and upscaling would result in great improvements in terms of electricity requirements and ozone consumption hence would bring down the environmental impact to values that are comparable to the biological process, suggesting that full scale implementation can be achieved. Further research should look into combining this treatment approach with technologies that allow water and salt recovery and reuse, to make the textile industry more sustainable.
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| 5. |
- Ali, Abukar, 1988, et al.
(author)
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IL-1 Receptor Antagonist Treatment Aggravates Staphylococcal Septic Arthritis and Sepsis in Mice.
- 2015
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In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7
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Journal article (peer-reviewed)abstract
- Interleukin-1 receptor antagonist (IL-1Ra) is the primary therapy against autoinflammatory syndromes with robust efficacy in reducing systemic inflammation and associated organ injury. However, patients receiving IL-1Ra might be at increased risk of acquiring serious infections.
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| 6. |
- Taheri, Javid, et al.
(author)
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Fuzzy Online Location Management in Mobile Computing Environments
- 2011
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In: Journal of Parallel and Distributed Computing. - : Academic Press. - 0743-7315 .- 1096-0848. ; 71:8, s. 1142-1153
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Journal article (peer-reviewed)abstract
- This paper presents a new approach, namely Intelligent Fuzzy Online Location Management Strategy (IFOLMS), based on Fuzzy clustering techniques to solve the mobile location management problem. Using a Fuzzy location estimator in this technique, mobile users' past movements are used in making future paging decisions by the network. IFOLMS has the potential to lead to massive savings in the number of network signal transactions that must be made to locate users. Performance of the proposed approach has been measured by using several test networks; it shows promising results - around 50% reduction in network cost - when compared to many of the existing location management techniques (including GSM). Results also provide new insights into the mobility management problem and its associated performance issues.
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