Articles de revistahttp://hdl.handle.net/2117/221892024-03-29T08:44:19Z2024-03-29T08:44:19ZContactless characterization of the elastic properties of glass microspheresMaire, JeremieNecio, TomaszChavez Angel, EmigdioColombano, M.FJaramillo Fernández, JulianaSotomayor Torres, Clivia M.Capuj, N.E.Navarro Urrios, Danielhttp://hdl.handle.net/2117/4049592024-03-25T01:41:31Z2024-03-19T14:58:58ZContactless characterization of the elastic properties of glass microspheres
Maire, Jeremie; Necio, Tomasz; Chavez Angel, Emigdio; Colombano, M.F; Jaramillo Fernández, Juliana; Sotomayor Torres, Clivia M.; Capuj, N.E.; Navarro Urrios, Daniel
Glass microspheres are of great interest for numerous industrial, biomedical, or standalone applications, but it remains challenging to evaluate their elastic and optical properties in a non-destructive way. In this work, we address this issue by using two complementary contactless tech- niques to obtain elastic and optical constants of glass microspheres with diameters ranging from 10 to 60 µm. The first technique we employ is Brillouin Light Scattering, which yields scattering with longitudinal acoustic phonons, the frequency of which is found to be 5% lower than that measured in the bulk material. The second technique involves exciting the optical whispering gallery modes of the microspheres, which allows us to transduce some of their vibrational modes. The combined data allow for extracting the refractive index and the elastic constants of the material. Our findings indicate that the values of those properties are reduced with respect to their bulk material counterpart due to an effective decrease of the density, resulting from the fabrication process. We propose the use of this combined method to extract elastic and optical parameters of glass materials in microsphere geometries and compare them with the values of the pristine material from which they are formed.
2024-03-19T14:58:58ZMaire, JeremieNecio, TomaszChavez Angel, EmigdioColombano, M.FJaramillo Fernández, JulianaSotomayor Torres, Clivia M.Capuj, N.E.Navarro Urrios, DanielGlass microspheres are of great interest for numerous industrial, biomedical, or standalone applications, but it remains challenging to evaluate their elastic and optical properties in a non-destructive way. In this work, we address this issue by using two complementary contactless tech- niques to obtain elastic and optical constants of glass microspheres with diameters ranging from 10 to 60 µm. The first technique we employ is Brillouin Light Scattering, which yields scattering with longitudinal acoustic phonons, the frequency of which is found to be 5% lower than that measured in the bulk material. The second technique involves exciting the optical whispering gallery modes of the microspheres, which allows us to transduce some of their vibrational modes. The combined data allow for extracting the refractive index and the elastic constants of the material. Our findings indicate that the values of those properties are reduced with respect to their bulk material counterpart due to an effective decrease of the density, resulting from the fabrication process. We propose the use of this combined method to extract elastic and optical parameters of glass materials in microsphere geometries and compare them with the values of the pristine material from which they are formed.Far-field radiative thermal rectification based on asymmetric emissivityNg, Ryan C.El Sachat, AlexandrosJaramillo Fernández, JulianaSotomayor Torres, Clivia M.Chavez Angel, Emigdiohttp://hdl.handle.net/2117/4049482024-03-19T13:50:21Z2024-03-19T13:40:28ZFar-field radiative thermal rectification based on asymmetric emissivity
Ng, Ryan C.; El Sachat, Alexandros; Jaramillo Fernández, Juliana; Sotomayor Torres, Clivia M.; Chavez Angel, Emigdio
This experimental study investigates thermal rectification via asymmetric far-field thermal radiation on a fused silica slab. An asymmetrical distribution of surface emissivity is created over the device by partially covering the fused silica with a 100 nm thick aluminum film. The slab is subjected to a thermal bias, and when this bias is reversed, a small temperature difference is observed between the different configurations. This temperature difference arises from the difference in emissivity between the aluminum layer and fused silica, resulting in the transfer of thermal energy to the surrounding environment through radiation. Experimental findings are supported by finite element simulations, which not only confirm the measured values but also provide valuable insights into the rectification efficiency of the system. The rectification efficiency is found to be approximately 50% at room temperature for a thermal bias of 140 K. Simulations, which are performed by considering different environmental conditions experienced by the radiation and free convection processes, provide further insight into the underlying thermal rectification mechanism. These simulations consider an environmental temperature of 4 K for thermal radiation and an ambient temperature of 294 K for free convection and reveal an enhanced rectification effect with a rectification efficiency up to 600% when a thermal bias of 195 K is applied. This result emphasizes the significance of considering both convection and radiation in the thermal management and rectification of asymmetric systems. The outcomes of this study further our understanding of the thermal rectification phenomenon. They also show the importance of system asymmetry, emissivity disparities, environmental conditions, and the interplay between convection and radiation. Furthermore, the findings have implications for heat transfer and rectification in asymmetric systems, offering potential applications in areas such as energy harvesting, thermal management, and heat transfer optimization in electronic devices.
2024-03-19T13:40:28ZNg, Ryan C.El Sachat, AlexandrosJaramillo Fernández, JulianaSotomayor Torres, Clivia M.Chavez Angel, EmigdioThis experimental study investigates thermal rectification via asymmetric far-field thermal radiation on a fused silica slab. An asymmetrical distribution of surface emissivity is created over the device by partially covering the fused silica with a 100 nm thick aluminum film. The slab is subjected to a thermal bias, and when this bias is reversed, a small temperature difference is observed between the different configurations. This temperature difference arises from the difference in emissivity between the aluminum layer and fused silica, resulting in the transfer of thermal energy to the surrounding environment through radiation. Experimental findings are supported by finite element simulations, which not only confirm the measured values but also provide valuable insights into the rectification efficiency of the system. The rectification efficiency is found to be approximately 50% at room temperature for a thermal bias of 140 K. Simulations, which are performed by considering different environmental conditions experienced by the radiation and free convection processes, provide further insight into the underlying thermal rectification mechanism. These simulations consider an environmental temperature of 4 K for thermal radiation and an ambient temperature of 294 K for free convection and reveal an enhanced rectification effect with a rectification efficiency up to 600% when a thermal bias of 195 K is applied. This result emphasizes the significance of considering both convection and radiation in the thermal management and rectification of asymmetric systems. The outcomes of this study further our understanding of the thermal rectification phenomenon. They also show the importance of system asymmetry, emissivity disparities, environmental conditions, and the interplay between convection and radiation. Furthermore, the findings have implications for heat transfer and rectification in asymmetric systems, offering potential applications in areas such as energy harvesting, thermal management, and heat transfer optimization in electronic devices.Designer SiO2 metasurfaces for efficient passive radiative coolingDing, ZhenminLi, HonglinLi, XinFan, XueyingJaramillo Fernández, JulianaPattelli, LorenzoZhao, JiupengNiu, ShichaoLi, YaoXu, Hongbohttp://hdl.handle.net/2117/3980582023-12-17T05:51:27Z2023-12-15T07:51:35ZDesigner SiO2 metasurfaces for efficient passive radiative cooling
Ding, Zhenmin; Li, Honglin; Li, Xin; Fan, Xueying; Jaramillo Fernández, Juliana; Pattelli, Lorenzo; Zhao, Jiupeng; Niu, Shichao; Li, Yao; Xu, Hongbo
In recent years, an increasing number of passive radiative cooling materials are proposed in the literature, with several examples relying on the use of silica (SiO2) due to its unique stability, non-toxicity, and availability. Nonetheless, due to its bulk phonon-polariton band, SiO2 presents a marked reflection peak within the atmospheric transparency window (8-13 µm), leading to an emissivity decrease that poses a challenge to fulfilling the criteria for sub-ambient passive radiative cooling. Thus, the latest developments in this field are devoted to the design of engineered SiO2 photonic structures, to increase the cooling potential of bulk SiO2 radiative coolers. This review seeks to identify the most effective photonic design and fabrication strategies for SiO2 radiative emitters by evaluating their cooling efficacy, as well as their scalability, providing an in-depth analysis of the fundamental principles, structural models, and results (both numerical and experimental) of various types of SiO2 radiative coolers.
2023-12-15T07:51:35ZDing, ZhenminLi, HonglinLi, XinFan, XueyingJaramillo Fernández, JulianaPattelli, LorenzoZhao, JiupengNiu, ShichaoLi, YaoXu, HongboIn recent years, an increasing number of passive radiative cooling materials are proposed in the literature, with several examples relying on the use of silica (SiO2) due to its unique stability, non-toxicity, and availability. Nonetheless, due to its bulk phonon-polariton band, SiO2 presents a marked reflection peak within the atmospheric transparency window (8-13 µm), leading to an emissivity decrease that poses a challenge to fulfilling the criteria for sub-ambient passive radiative cooling. Thus, the latest developments in this field are devoted to the design of engineered SiO2 photonic structures, to increase the cooling potential of bulk SiO2 radiative coolers. This review seeks to identify the most effective photonic design and fabrication strategies for SiO2 radiative emitters by evaluating their cooling efficacy, as well as their scalability, providing an in-depth analysis of the fundamental principles, structural models, and results (both numerical and experimental) of various types of SiO2 radiative coolers.Inclusion of the gender equality sustainable development goal in engineering teaching and researchPeña Carrera, MartaMas de les Valls Ortiz, Elisabethttp://hdl.handle.net/2117/3977962023-12-17T05:43:54Z2023-12-12T10:39:54ZInclusion of the gender equality sustainable development goal in engineering teaching and research
Peña Carrera, Marta; Mas de les Valls Ortiz, Elisabet
This work explores how gender mainstreaming can be included in the teaching and research of engineering, a framed discipline belonging to Science, Technology, Engineering and Mathematics (known with the acronym STEM), an area of knowledge known for having (especially in the Western countries) a low proportion of female students. There is little research and manuals that address gender-specifc issues in this area of knowledge and how they could be addressed. During the 2018/2019 academic year, a pilot project on gender mainstreaming was carried out at the Universitat Politècnica de Catalunya – BarcelonaTech (UPC) as part of these actions. For this purpose, 41 voluntary teachers from 8 Bachelor’s and Master’s Degrees of the UPC have been recruited. Social and gender relevance of the subjects, inclusive methodology, classroom management and assessment have been considered in this research. One of the tools obtained from this study is a guide of recommendations to be used by the teaching and research staf to introduce the changes that make possible the efective incorporation of the gender equality Sustainable Development Goal (SDG) in engineering teaching and research. The recommendations proposed in this work derive from the research carried out for this project. The work, therefore, paves the way for further insight into the specifc gender bias in engineering and is an essential tool for people involved in teaching and research in the engineering feld from a critical spirit.
2023-12-12T10:39:54ZPeña Carrera, MartaMas de les Valls Ortiz, ElisabetThis work explores how gender mainstreaming can be included in the teaching and research of engineering, a framed discipline belonging to Science, Technology, Engineering and Mathematics (known with the acronym STEM), an area of knowledge known for having (especially in the Western countries) a low proportion of female students. There is little research and manuals that address gender-specifc issues in this area of knowledge and how they could be addressed. During the 2018/2019 academic year, a pilot project on gender mainstreaming was carried out at the Universitat Politècnica de Catalunya – BarcelonaTech (UPC) as part of these actions. For this purpose, 41 voluntary teachers from 8 Bachelor’s and Master’s Degrees of the UPC have been recruited. Social and gender relevance of the subjects, inclusive methodology, classroom management and assessment have been considered in this research. One of the tools obtained from this study is a guide of recommendations to be used by the teaching and research staf to introduce the changes that make possible the efective incorporation of the gender equality Sustainable Development Goal (SDG) in engineering teaching and research. The recommendations proposed in this work derive from the research carried out for this project. The work, therefore, paves the way for further insight into the specifc gender bias in engineering and is an essential tool for people involved in teaching and research in the engineering feld from a critical spirit.Estimating fishing effort from highly resolved geospatial data: Focusing on passive gearsMendo, TaniaGlemarec, GildasMendo Aguilar, Jaime HumbertoHjorleifsson, EinarSmout, Sophie CarolineNorthridge, SimonRodriguez, JulienMujal Colilles, AnnaJames, Mark Andrewhttp://hdl.handle.net/2117/3969562023-11-26T21:43:55Z2023-11-23T15:13:49ZEstimating fishing effort from highly resolved geospatial data: Focusing on passive gears
Mendo, Tania; Glemarec, Gildas; Mendo Aguilar, Jaime Humberto; Hjorleifsson, Einar; Smout, Sophie Caroline; Northridge, Simon; Rodriguez, Julien; Mujal Colilles, Anna; James, Mark Andrew
Increasing competition for marine space requires the appropriate development of indicators to best represent the use of marine areas and the value (whether economic, social and/or cultural) derived from such use. Fishers (the largest group of users) are often under-represented in marine spatial planning processes. Highly-resolved vessel tracking data provide opportunities to map the activities of fishing vessels at a level of detail never before available. Most effort mapping methods have focused on active gears such as trawls or dredges in large scale fisheries. For these fisheries, the time spent fishing at sea (hours) is usually a representative indicator of fishing effort, enabling a straightforward mapping of the most important fishing grounds. However, for passive gears generally used in small-scale fisheries, we show that spatial indicators of effort (here, length of vessel track) greatly outperform time-at-sea as an indicator of fishing effort. We further demonstrate and validate a method to estimate gear soak time from vessel tracking data and show how maps of effort that account for soak time can be different from those solely based on time spent fishing at sea. The development of adequate methods to quantify the spatial distribution of passive gear effort is particularly relevant to fisheries management because globally about a fifth of all catches (by weight) are landed by passive gears. Appropriate, fine scale effort maps will provide better tools for spatial planning to support sustainable fishing.
2023-11-23T15:13:49ZMendo, TaniaGlemarec, GildasMendo Aguilar, Jaime HumbertoHjorleifsson, EinarSmout, Sophie CarolineNorthridge, SimonRodriguez, JulienMujal Colilles, AnnaJames, Mark AndrewIncreasing competition for marine space requires the appropriate development of indicators to best represent the use of marine areas and the value (whether economic, social and/or cultural) derived from such use. Fishers (the largest group of users) are often under-represented in marine spatial planning processes. Highly-resolved vessel tracking data provide opportunities to map the activities of fishing vessels at a level of detail never before available. Most effort mapping methods have focused on active gears such as trawls or dredges in large scale fisheries. For these fisheries, the time spent fishing at sea (hours) is usually a representative indicator of fishing effort, enabling a straightforward mapping of the most important fishing grounds. However, for passive gears generally used in small-scale fisheries, we show that spatial indicators of effort (here, length of vessel track) greatly outperform time-at-sea as an indicator of fishing effort. We further demonstrate and validate a method to estimate gear soak time from vessel tracking data and show how maps of effort that account for soak time can be different from those solely based on time spent fishing at sea. The development of adequate methods to quantify the spatial distribution of passive gear effort is particularly relevant to fisheries management because globally about a fifth of all catches (by weight) are landed by passive gears. Appropriate, fine scale effort maps will provide better tools for spatial planning to support sustainable fishing.Simulation of flash floods in ungauged basins using post-event surveys and numerical modellingCiervo, FabioPapa, Maria NicolinaMedina Iglesias, Vicente César deBateman Pinzón, Allenhttp://hdl.handle.net/2117/3936602023-09-25T01:26:45Z2023-09-19T10:25:40ZSimulation of flash floods in ungauged basins using post-event surveys and numerical modelling
Ciervo, Fabio; Papa, Maria Nicolina; Medina Iglesias, Vicente César de; Bateman Pinzón, Allen
The hydrological and hydraulic processes of the flash flood that affected Atrani village (Amalfi Coast of Southern Italy) on 9 September 2010 are analysed using post-flood surveys and numerical modelling. Observations in this case are particularly challenging because of the small spatial and temporal scales of the event, relative to the sampling characteristics of conventional rain and discharge measurement networks. Given these aspects, some of the relevant characteristics of the event were deduced by analysing field data that were collected immediately after the event. A width function instantaneous unit hydrograph (WFIUH) rainfall-runoff model is applied to derive a flow hydrograph for the area immediately upstream of the village. This hydrograph is inputted as an upstream boundary condition for the simulation of the propagation processes. A two-dimensional innovative hydraulic model is used to reproduce the flood within the village. The use of an unstructured mesh enabled a detailed simulation of water flow within the narrow and winding alleyways of the village. The results of the simulations indicate agreement with the field observations. The implemented approach is suitable for simulating flash floods in similar contexts and, therefore, may be used to predict potential future events.
2023-09-19T10:25:40ZCiervo, FabioPapa, Maria NicolinaMedina Iglesias, Vicente César deBateman Pinzón, AllenThe hydrological and hydraulic processes of the flash flood that affected Atrani village (Amalfi Coast of Southern Italy) on 9 September 2010 are analysed using post-flood surveys and numerical modelling. Observations in this case are particularly challenging because of the small spatial and temporal scales of the event, relative to the sampling characteristics of conventional rain and discharge measurement networks. Given these aspects, some of the relevant characteristics of the event were deduced by analysing field data that were collected immediately after the event. A width function instantaneous unit hydrograph (WFIUH) rainfall-runoff model is applied to derive a flow hydrograph for the area immediately upstream of the village. This hydrograph is inputted as an upstream boundary condition for the simulation of the propagation processes. A two-dimensional innovative hydraulic model is used to reproduce the flood within the village. The use of an unstructured mesh enabled a detailed simulation of water flow within the narrow and winding alleyways of the village. The results of the simulations indicate agreement with the field observations. The implemented approach is suitable for simulating flash floods in similar contexts and, therefore, may be used to predict potential future events.Comparison of different hydrological and stability assumptions for physically-based modeling of shallow landslidesDurmaz, MuhammetHurlimann Ziegler, MarcelHuvaj, NejanMedina Iglesias, Vicente César dehttp://hdl.handle.net/2117/3924422023-07-31T00:02:48Z2023-07-27T16:46:57ZComparison of different hydrological and stability assumptions for physically-based modeling of shallow landslides
Durmaz, Muhammet; Hurlimann Ziegler, Marcel; Huvaj, Nejan; Medina Iglesias, Vicente César de
Physically-based models are reliable techniques for landslide susceptibility assessment, therefore, several models have been proposed in the literature. In this study, two different hydrological models (FSLAM and TRIGRS) and two slope stability calculation methods (infinite slope and limit equilibrium method with spherical failure surface in SCOOPS3D) were compared. The rainfall-triggered shallow landslides that occurred in Kaptanpasa, Rize (Turkey) in 2017 were selected as a case study. The main focus is investigating the impact of landslide morphology on the success of the slope stability models. For this purpose, landslides in the inventory were grouped according to their morphological characteristics, such as the landslide depth, length, width and their ratios, and their compatibility with model assumptions (e.g. the infinite slope assumption). Then, the model performances in different landslide types were evaluated separately. To calibrate the model parameters a new time-saving, semi-automated calibration strategy, based on a sensitivity analysis, is proposed. Concretely, stability parameters were calibrated via a MATLAB code by considering the area under the curve (AUC) and extreme conditions: saturated and initial conditions. Overall, SCOOPS3D is deduced to have better performance than infinite slope analysis. However, the accuracy of SCOOPS3D is revealed to decrease for landslides with a high ratio of length/depth and width/depth. From the comparison of hydrological models, FSLAM yielded more plausible results than TRIGRS with the available data. It is demonstrated that the morphological features of the landslides significantly influence the performance of the physically-based stability models. Furthermore, it is highlighted that the resolution of the Digital Elevation Model in comparison to the width and length of the landslides in an inventory can be influential in the performance of the physical model. 10 m resolution of DEM is deemed to be suitable for the study area judging the predictive performance in small landslides.
2023-07-27T16:46:57ZDurmaz, MuhammetHurlimann Ziegler, MarcelHuvaj, NejanMedina Iglesias, Vicente César dePhysically-based models are reliable techniques for landslide susceptibility assessment, therefore, several models have been proposed in the literature. In this study, two different hydrological models (FSLAM and TRIGRS) and two slope stability calculation methods (infinite slope and limit equilibrium method with spherical failure surface in SCOOPS3D) were compared. The rainfall-triggered shallow landslides that occurred in Kaptanpasa, Rize (Turkey) in 2017 were selected as a case study. The main focus is investigating the impact of landslide morphology on the success of the slope stability models. For this purpose, landslides in the inventory were grouped according to their morphological characteristics, such as the landslide depth, length, width and their ratios, and their compatibility with model assumptions (e.g. the infinite slope assumption). Then, the model performances in different landslide types were evaluated separately. To calibrate the model parameters a new time-saving, semi-automated calibration strategy, based on a sensitivity analysis, is proposed. Concretely, stability parameters were calibrated via a MATLAB code by considering the area under the curve (AUC) and extreme conditions: saturated and initial conditions. Overall, SCOOPS3D is deduced to have better performance than infinite slope analysis. However, the accuracy of SCOOPS3D is revealed to decrease for landslides with a high ratio of length/depth and width/depth. From the comparison of hydrological models, FSLAM yielded more plausible results than TRIGRS with the available data. It is demonstrated that the morphological features of the landslides significantly influence the performance of the physically-based stability models. Furthermore, it is highlighted that the resolution of the Digital Elevation Model in comparison to the width and length of the landslides in an inventory can be influential in the performance of the physical model. 10 m resolution of DEM is deemed to be suitable for the study area judging the predictive performance in small landslides.The energy transfer from granular landslides to water bodies explained by a data-driven, physics-based numerical modelBregoli, FrancescoMedina Iglesias, Vicente César deBateman Pinzón, Allenhttp://hdl.handle.net/2117/3885532023-06-18T19:03:34Z2023-06-13T10:36:31ZThe energy transfer from granular landslides to water bodies explained by a data-driven, physics-based numerical model
Bregoli, Francesco; Medina Iglesias, Vicente César de; Bateman Pinzón, Allen
Time trends and their statistical significance for daily minimum, Tmin, and maximum, Tmax, temperatures recorded at the Fabra Observatory (Barcelona) along 102 years (1917–2018) permit to analyse the evolution of every one of the 365 calendar days along the recording period. Relevant changes in the daily temperature regime have been quantified not only by time trends and the Mann–Kendall test, but also by the multifractal analysis applied to consecutive segments of daily temperature data. The evolution of several multifractal parameters (the central Hölder exponent, the spectral asymmetry and spectral amplitude, the complexity index and the Hurst exponent) provides a complementary viewpoint to describe the evolution of the thermometric regime along the 102 recorded years. At monthly scale, the effects of the climate change are characterised by significant positive trends from September to December and very moderate negative trends from April to July. With respect to changes in the calendar-day structure, it is noticeable a shift of the highest minimum and maximum daily temperature from July to August (year 2018) to the beginning of September (projections for years 2030 and 2050) and the projected highest maximum calendar-day temperature exceeding 30 °C.
The version of record os available online at: http://dx.doi.org/10.1007/s10346-020-01568-3
2023-06-13T10:36:31ZBregoli, FrancescoMedina Iglesias, Vicente César deBateman Pinzón, AllenTime trends and their statistical significance for daily minimum, Tmin, and maximum, Tmax, temperatures recorded at the Fabra Observatory (Barcelona) along 102 years (1917–2018) permit to analyse the evolution of every one of the 365 calendar days along the recording period. Relevant changes in the daily temperature regime have been quantified not only by time trends and the Mann–Kendall test, but also by the multifractal analysis applied to consecutive segments of daily temperature data. The evolution of several multifractal parameters (the central Hölder exponent, the spectral asymmetry and spectral amplitude, the complexity index and the Hurst exponent) provides a complementary viewpoint to describe the evolution of the thermometric regime along the 102 recorded years. At monthly scale, the effects of the climate change are characterised by significant positive trends from September to December and very moderate negative trends from April to July. With respect to changes in the calendar-day structure, it is noticeable a shift of the highest minimum and maximum daily temperature from July to August (year 2018) to the beginning of September (projections for years 2030 and 2050) and the projected highest maximum calendar-day temperature exceeding 30 °C.Shallow landslide susceptibility assessment under future climate and land cover changes: a case study from southwest ChinaGuo, ZizhengFerrer, Joaquin Vicente ConsunjiHurlimann Ziegler, MarcelMedina Iglesias, Vicente César dePuig i Polo, CàrolYin, KunlongHuang, Dahttp://hdl.handle.net/2117/3853992023-03-26T19:44:05Z2023-03-23T19:03:00ZShallow landslide susceptibility assessment under future climate and land cover changes: a case study from southwest China
Guo, Zizheng; Ferrer, Joaquin Vicente Consunji; Hurlimann Ziegler, Marcel; Medina Iglesias, Vicente César de; Puig i Polo, Càrol; Yin, Kunlong; Huang, Da
There is no doubt that land cover and climate changes have consequences on landslide activity, but it is still an open issue to assess and quantify their impacts. Wanzhou County in southwest China was selected as the test area to study rainfall-induced shallow landslide susceptibility under the future changes of land use and land cover (LULC) and climate. We used a high-resolution meteorological precipitation dataset and frequency distribution model to analyse the present extreme and antecedent rainfall conditions related to landslide activity. The future climate change factors were obtained from a 4-member multi-model ensemble that was derived from statistically downscaled regional climate simulations. The future LULC maps were simulated by the land change modeller (LCM) integrated into IDRISI Selva software. A total of six scenarios were defined by considering the rainfall (antecedent conditions and extreme events) and LULC changes towards two time periods (mid and late XXI century). A physically-based model was used to assess landslide susceptibility under these different scenarios. The results showed that the magnitude of both antecedent effective recharge and event rainfall in the region will evidently increase in the future. Under the scenario with a return period of 100 years, the antecedent rainfall in summer will increase by up to 63% whereas the event rainfall will increase by up to 54% for the late 21st century. The most considerable changes of LULC will be the increase of forest cover and the decrease of farming land. The magnitude of this change can reach + 22.1% (forest) and –9.2% (farmland) from 2010 until 2100, respectively. We found that the negative impact of climate change on landslide susceptibility is greater than the stabilizing effect of LULC change, leading to an over decrease in stability over the study area. This is one of the first studies across Asia to assess and quantify changes of regional landslide susceptibility under scenarios driven by LULC and climate change. Our results aim to guide land use planning and climate change mitigation considerations to reduce landslide risk.
2023-03-23T19:03:00ZGuo, ZizhengFerrer, Joaquin Vicente ConsunjiHurlimann Ziegler, MarcelMedina Iglesias, Vicente César dePuig i Polo, CàrolYin, KunlongHuang, DaThere is no doubt that land cover and climate changes have consequences on landslide activity, but it is still an open issue to assess and quantify their impacts. Wanzhou County in southwest China was selected as the test area to study rainfall-induced shallow landslide susceptibility under the future changes of land use and land cover (LULC) and climate. We used a high-resolution meteorological precipitation dataset and frequency distribution model to analyse the present extreme and antecedent rainfall conditions related to landslide activity. The future climate change factors were obtained from a 4-member multi-model ensemble that was derived from statistically downscaled regional climate simulations. The future LULC maps were simulated by the land change modeller (LCM) integrated into IDRISI Selva software. A total of six scenarios were defined by considering the rainfall (antecedent conditions and extreme events) and LULC changes towards two time periods (mid and late XXI century). A physically-based model was used to assess landslide susceptibility under these different scenarios. The results showed that the magnitude of both antecedent effective recharge and event rainfall in the region will evidently increase in the future. Under the scenario with a return period of 100 years, the antecedent rainfall in summer will increase by up to 63% whereas the event rainfall will increase by up to 54% for the late 21st century. The most considerable changes of LULC will be the increase of forest cover and the decrease of farming land. The magnitude of this change can reach + 22.1% (forest) and –9.2% (farmland) from 2010 until 2100, respectively. We found that the negative impact of climate change on landslide susceptibility is greater than the stabilizing effect of LULC change, leading to an over decrease in stability over the study area. This is one of the first studies across Asia to assess and quantify changes of regional landslide susceptibility under scenarios driven by LULC and climate change. Our results aim to guide land use planning and climate change mitigation considerations to reduce landslide risk.Validation and verification of a quasi two-dimensional turbulence model and an eddy detection method for liquid metal magnetohydrodynamics flowsSuárez Cambra, DanielIraola de Acevedo, EduardoSerrat Serra, JoaquimMas de les Valls Ortiz, ElisabetFutatani, ShimpeiBatet Miracle, Lluíshttp://hdl.handle.net/2117/3852052024-03-01T01:29:17Z2023-03-20T10:51:08ZValidation and verification of a quasi two-dimensional turbulence model and an eddy detection method for liquid metal magnetohydrodynamics flows
Suárez Cambra, Daniel; Iraola de Acevedo, Eduardo; Serrat Serra, Joaquim; Mas de les Valls Ortiz, Elisabet; Futatani, Shimpei; Batet Miracle, Lluís
The flow of liquid metals in straight rectangular channels with an externally applied transverse magnetic field is considered for breeding blankets in tokamak fusion reactors. Under the tokamak magnetic field, the liquid metal experiences the magnetohydrodynamic (MHD) effect that enhances the laminarization of the flow. In geometric singularities, or under certain flow conditions, the combination of Lorentz forces, momentum, and buoyant forces may trigger the formation of vortical structures. The generated vortices will align with the direction of the magnetic field, and therefore the use of a quasi-two-dimensional (Q2D) model is convenient to study them assuming that the walls are electrically insulating and the Hartmann number $\textbf{Ha} = B L \sqrt{\sigma/\mu}$ is high enough. Using this model is computationally affordable, allowing extensive parametric analyses. To identify the presence of eddies in the two-dimensional domain, the application of the bi-dimensional fast Fourier transform (FFT2) is foreseen as an adequate detection method. This work presents a methodology to systematically calculate liquid metal MHD flows with a Q2D model and evaluate the formation of eddies in the flow domain. The work includes a description of the validation and verification of the Q2D MHD model and of the FFT2 method proposed to automatically identify eddies. The sensitivity of the detection method is analyzed to subsequently apply it in parametric analyses.
2023-03-20T10:51:08ZSuárez Cambra, DanielIraola de Acevedo, EduardoSerrat Serra, JoaquimMas de les Valls Ortiz, ElisabetFutatani, ShimpeiBatet Miracle, LluísThe flow of liquid metals in straight rectangular channels with an externally applied transverse magnetic field is considered for breeding blankets in tokamak fusion reactors. Under the tokamak magnetic field, the liquid metal experiences the magnetohydrodynamic (MHD) effect that enhances the laminarization of the flow. In geometric singularities, or under certain flow conditions, the combination of Lorentz forces, momentum, and buoyant forces may trigger the formation of vortical structures. The generated vortices will align with the direction of the magnetic field, and therefore the use of a quasi-two-dimensional (Q2D) model is convenient to study them assuming that the walls are electrically insulating and the Hartmann number $\textbf{Ha} = B L \sqrt{\sigma/\mu}$ is high enough. Using this model is computationally affordable, allowing extensive parametric analyses. To identify the presence of eddies in the two-dimensional domain, the application of the bi-dimensional fast Fourier transform (FFT2) is foreseen as an adequate detection method. This work presents a methodology to systematically calculate liquid metal MHD flows with a Q2D model and evaluate the formation of eddies in the flow domain. The work includes a description of the validation and verification of the Q2D MHD model and of the FFT2 method proposed to automatically identify eddies. The sensitivity of the detection method is analyzed to subsequently apply it in parametric analyses.