Feasibility Study of Hydrochar/Zn composites in Heterogeneous Photocatalytic Degradation

Treballs Finals de Grau d'Enginyeria Química, Facultat de Química, Universitat de Barcelona, Curs: 2023-2024, Tutora: Pilar Marco BujWater pollution has become an increasingly severe environmental problem. This increase is due to industrial factors and the growing demand for water by the population. This situation is aggravated by the drought problem in Catalonia, which intensifies the pressure on available water resources. With its rich wine-growing tradition, Catalonia generates a large amount of agricultural waste after the grape harvest each year, mainly from the vine shoots. These residues can be converted into hydrochar (HC), a material that is effective in adsorption and photocatalysis processes when combined with other oxides. Considering these factors, interest arises in recycling organic waste into hydrochar (HC) and using it in heterogeneous photocatalytic degradation processes (one of the AOPs techniques) to eliminate emerging pollutants. This approach offers a more sustainable, economical and ecological solution to address drought and improve water quality. This project is proposed to evaluate the feasibility and efficiency of HC and HC/Zn composites in the photodegradation of metoprolol and thiacloprid pollutants under UV irradiation. The aim was to synthesize these composites and analyze their photocatalytic effectiveness and their reusability through multiple degradation cycles. The results showed that individual HC achieved a significant degradation percentage, with 19.91% for metoprolol and 16.89% for thiacloprid after 3 hours of UV illumination. Among the synthesized photocatalysts, HC-HDZn 10% achieved the highest photocatalytic activity, reaching degradation efficiencies of 99.82% for metoprolol and 98.27% for thiacloprid. The study also analyzed the reuse of the optimal photocatalyst in multiple degradation cycles, showing a slight decrease in efficiency but maintaining more than 90% of its initial capacity after three cycles. These results indicate that HC and its composites are promising materials in the photodegradation of organic pollutants, proving successful in environmental remediation applications due to their sustainable, stable character and high efficiency. Future studies could further optimize these materials and explore their application to a wider variety of pollutants

The Minimal GUT with Inflaton and Dark Matter Unification

Giving up the solutions to the fine-tuning problems, we propose the non-supersymmetric flipped $SU(5)\times U(1)_X$ model based on the minimal particle content principle, which can be constructed from the four-dimensional $SO(10)$ models, five-dimensional orbifold $SO(10)$ models, and local F-theory $SO(10)$ models. To achieve gauge coupling unification, we introduce one pair of vector-like fermions, which form complete $SU(5)\times U(1)_X$ representation. Proton lifetime is around $5\times 10^{35}$ years, neutrino masses and mixing can be explained via seesaw mechanism, baryon asymmetry can be generated via leptogenesis, and vacuum stability problem can be solved as well. In particular, we propose that inflaton and dark matter particle can be unified to a real scalar field with $Z_2$ symmetry, which is not an axion and does not have the non-minimal coupling to gravity. Such kind of scenarios can be applied to the generic scalar dark matter models. Also, we find that the vector-like particle corrections to the $B_s^0$ masses can be about 6.6%, while their corrections to the $K^0$ and $B_d^0$ masses are negligible.Comment: 5 pages, 4 figures;V2: published versio

Supergravity inflation on a brane

We discuss supergravity inflation in braneworld cosmology for the class of potentials $V(\phi)=\alpha \phi^n\rm{exp}(-\beta^m \phi^m)$ with $m=1,~2$. These minimal SUGRA models evade the $\eta$ problem due to a broken shift symmetry and can easily accommodate the observational constraints. Models with smaller $n$ are preferred while models with larger $n$ are out of the $2\sigma$ region. Remarkably, the field excursions required for $60$ $e$-foldings stay sub-planckian $\Delta\phi <1$.Comment: 10 pages, 4 figure

A 3-D Projection Model for X-ray Dark-field Imaging

Talbot-Lau X-ray phase-contrast imaging is a novel imaging modality, which provides not only an X-ray absorption image, but also additionally a differential phase image and a dark-field image. The dark-field image is related to small angle scattering and has an interesting property when canning oriented structures: the recorded signal depends on the relative orientation of the structure in the imaging system. Exactly this property allows to draw conclusions about the orientation and to reconstruct the structure. However, the reconstruction is a complex, non-trivial challenge. A lot of research was conducted towards this goal in the last years and several reconstruction algorithms were proposed. A key step of the reconstruction algorithm is the inversion of a forward projection model. Up until now, only 2-D projection models are available, with effectively limit the scanning trajectory to a 2-D plane. To obtain true 3-D information, this limitation requires to combine several 2-D scans, which leads to quite complex, impractical acquisitions schemes. Furthermore, it is not possible with these models to use 3-D trajectories that might allow simpler protocols, like for example a helical trajectory. To address these limitations, we propose in this work a very general 3-D projection model. Our projection model defines the dark-field signal dependent on an arbitrarily chosen ray and sensitivity direction. We derive the projection model under the assumption that the observed scatter distribution has a Gaussian shape. We theoretically show the consistency of our model with more constrained existing 2-D models. Furthermore, we experimentally show the compatibility of our model with dark-field measurements of two matchsticks. We believe that this 3-D projection model is an important step towards more flexible trajectories and imaging protocols that are much better applicable in practice.Comment: Shiyang Hu and Lina Felsner contributed equally to this wor

Sustainable development for Chinese urban heritage tourism: Insights from travelers in Shanghai

As a widely-recognized destination for heritage tourism, China has attracted considerable amount of tourists from both domestically and internationally. Given the delicate nature of heritage in urban areas, this study paid special attention to the sustainable Chinese urban heritage tourism development from travelers’ perspectives based in Shanghai. Such perspectives are taken because their experiences perceived at popular urban heritage tourism attractions are the final tourism products. The authors explored the major factors that impact travelers’ experiences in urban heritage tourism, including visitation environment, economic impact, and community development. Considering the Chinese urban areas tend to be highly populated and undergoing constructions, such insights should facilitate decision makers to achieve the balance between heritage protection and tourism development in urban areas