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Spatial and Temporal Validation of In-Situ and Satellite Weather Data for the South West Agricultural Region of Australia

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Journal of Meteorological Research 2022年第1期36卷 175-192页

作者： tristan campbell Peter FEARNS Centre for Mine Site Restoration Curtin University of TechnologyWA 6102Australia Remote Sensing and Satellite Research Group Curtin University of TechnologyWA 6102Australia

Seasonal variations in weather have significant impacts on crop yields.The accuracy of weather data is an important consideration for crop yield models.This study uses an independent in-situ weather station network to validate the accuracy of monthly temperature and precipitation data from the in-situ weather station network operated by the Bureau of Meteorology(BOM),interpolated gridded data from this network,and satellite weather data for the South West Agricultural Region of Australia.This region covers five classes of the K?ppen-Geiger climate classification system and is responsible for 10 billion AUD of agricultural produce annually.A strong bias was found for the maximum temperatures in the Copernicus LST(land surface temperature)satellite product.This bias was linearly correlated with the in-situ temperature and exceeded 20℃in warmer months.Due to the bias’s linear nature,a linear correction was able to reduce the root-mean-square error(RMSE)of the Copernicus LST product by 82%.This process was tested for other regions of Australia and,despite some regional differences,a linear correction consistently reduced RMSE by 80%.The validation process demonstrated that the dataset with reliably the lowest RMSE is the gridded weather data calculated from BOM’s in-situ weather stations.Nearest neighbor in-situ weather stations generally had the next lowest RMSE,followed by weather-station corrected satellite products and lastly the non-weather station corrected satellite products.While the in-situ gridded product generally had the lowest RMSE,there were spatial and seasonal variations.Monthly maximum temperatures were more accurately measured by the bias-corrected Copernicus LST product in the northern and eastern extents(where there is a lower density of BOM in-situ stations).Monthly minimum temperatures from the Copernicus LST product had similar to slightly better RMSE than the Australian Water Availability Project(AWAP)product for the southern half of the study area and the rain-gauge corrected GSMaP(Global Sat

关键词： Australian Water Availability Project land surface temperature satellite precipitation validation

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Discontinuous Galerkin Methods for a Class of Nonvariational Problems

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Communications on Applied Mathematics and Computation 2022年第2期4卷 634-656页

作者： Andreas Dedner tristan Pryer Mathematics Institute University of WarwickCoventry CV47ALUK Department of Mathematical Sciences University of BathBath BA27AYUK

We extend the fnite element method introduced by Lakkis and Pryer(SIAM J.Sci.Comput.33(2):786–801,2011)to approximate the solution of second-order elliptic problems in nonvariational form to incorporate the discontinuous Galerkin(DG)framework.This is done by viewing the“fnite element Hessian”as an auxiliary variable in the formulation.Representing the fnite element Hessian in a discontinuous setting yields a linear system of the same size and having the same sparsity pattern of the compact DG methods for variational elliptic problems.Furthermore,the system matrix is very easy to assemble;thus,this approach greatly reduces the computational complexity of the discretisation compared to the continuous approach.We conduct a stability and consistency analysis making use of the unifed frameworkset out in Arnold et al.(SIAM J.Numer.Anal.39(5):1749–1779,2001/2002).We also give an a posteriori analysis of the method in the case where the problem has a strong solution.The analysis applies to any consistent representation of the fnite element Hessian,and thus is applicable to the previous works making use of continuous Galerkin approximations.Numerical evidence is presented showing that the method works well also in a more general setting.

关键词： Nonvariational problems Discontinuous Galerkin Error estimates Adaptivity

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Mock catalogues for large surveys:Lessons from Gaia and implications for CSST

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Science China(Physics,Mechanics & Astronomy) 2023年第11期66卷 239-240页

作者： tristan Cantat-Gaudin Max-Planck-Institut für Astronomie Heidelberg69117Germany

Experience in large stellar surveys,such as Gaia,has shown that synthetic catalogues are very useful for preparing the data and evaluating scientific results(see the Gaia Universe model snapshot,ref.[1],as an example).This experience holds especially for complex datasets that provide not only positions and apparent magnitudes,but also proper motions,multi-band photometry,and spectroscopy.

关键词： spectroscopy survey holds

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ARHCS (Automatic Rainfall Half-Life Cluster System): A Landslides Early Warning System (LEWS) Using Cluster Analysis and Automatic Threshold Definition

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International Journal of Geosciences 2024年第1期15卷 54-69页

作者： Cassiano Antonio Bortolozo Luana Albertani Pampuch Marcio Roberto Magalhães De Andrade Daniel Metodiev Adenilson Roberto Carvalho Tatiana Sussel Gonçalves Mendes tristan Pryer Harideva Marturano Egas Rodolfo Moreda Mendes Isadora Araújo Sousa Jenny Power Cemaden - National Center for Monitoring and Early Warning of Natural Disasters General Coordination of Research and Development S&#227o José dos Campos Brazil Environmental Engineering Department Institute of Science and Technology S&#227o Paulo State University S&#227o José dos Campos Brazil Department of Mathematical Sciences University of Bath Bath UK Institute for Mathematical Innovation University of Bath Bath UK

A significant portion of Landslide Early Warning Systems (LEWS) relies on the definition of operational thresholds and the monitoring of cumulative rainfall for alert issuance. These thresholds can be obtained in various ways, but most often they are based on previous landslide data. This approach introduces several limitations. For instance, there is a requirement for the location to have been previously monitored in some way to have this type of information recorded. Another significant limitation is the need for information regarding the location and timing of incidents. Despite the current ease of obtaining location information (GPS, drone images, etc.), the timing of the event remains challenging to ascertain for a considerable portion of landslide data. Concerning rainfall monitoring, there are multiple ways to consider it, for instance, examining accumulations over various intervals (1 h, 6 h, 24 h, 72 h), as well as in the calculation of effective rainfall, which represents the precipitation that actually infiltrates the soil. However, in the vast majority of cases, both the thresholds and the rain monitoring approach are defined manually and subjectively, relying on the operators’ experience. This makes the process labor-intensive and time-consuming, hindering the establishment of a truly standardized and rapidly scalable methodology on a large scale. In this work, we propose a Landslides Early Warning System (LEWS) based on the concept of rainfall half-life and the determination of thresholds using Cluster Analysis and data inversion. The system is designed to be applied in extensive monitoring networks, such as the one utilized by Cemaden, Brazil’s National Center for Monitoring and Early Warning of Natural Disasters.

关键词： Landslides Early Warning System (LEWS) Cluster Analysis Landslides Brazil

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Impact of interconnections and renewable energy integration on the Philippine-Sabah Power Grid systems

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Global Energy Interconnection 2023年第3期6卷 253-272页

作者： tristan G.Magallones,Jr. Jai Govind Singh Department of Energy Environment and Climate ChangeSERDAsian Institute of TechnologyPathumthani 12120Thailand Department of Electrical Engineering Central Mindanao UniversityBukidnon 8710Philippines

This study presents a comprehensive impact analysis of the rotor angle stability of a proposed international connection between the Philippines and Sabah,Malaysia,as part of the Association of Southeast Asian Nations(ASEAN)Power Grid.This study focuses on modeling and evaluating the dynamic performance of the interconnected system,considering the high penetration of renewable sources.Power flow,small signal stability,and transient stability analyses were conducted to assess the ability of the proposed linked power system models to withstand small and large disturbances,utilizing the Power Systems Analysis Toolbox(PSAT)software in MATLAB.All components used in the model are documented in the PSAT library.Currently,there is a lack of publicly available studies regarding the implementation of this specific system.Additionally,the study investigates the behavior of a system with a high penetration of renewable energy sources.Based on the findings,this study concludes that a system is generally stable when interconnection is realized,given its appropriate location and dynamic component parameters.Furthermore,the critical eigenvalues of the system also exhibited improvement as the renewable energy sources were augmented.

关键词： Modeling of ASEAN Power Grid Rotor angle stability of asynchronous Philippine-Sabah interconnection in ASEAN Power Grid The impact of renewable energy integration on Philippine-Sabah interconnection in ASEAN Power Grid

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Dry reforming of methane on doped Ni nanoparticles:Featureassisted optimizations and ranking of doping metals for direct activations of CH_(4) and CO_(2)

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Nano Research 2022年第10期15卷 9670-9682页

作者： Shiru Lin Jean-Baptiste tristan Yang Wang Junwei Lucas Bao Department of Chemistry Boston CollegeChestnut HillMassachusetts 02467USA Department of Computer Science Boston CollegeChestnut HillMassachusetts 02467USA

As a vital energy resource and raw material for many industrial products,syngas(CO and H_(2))is of great significance.Dry reforming of methane(DRM)is an important approach to producing syngas(with a hydrogen-to-carbon-monoxide ratio of 1:1 in principle)from methane and carbon dioxide,with a lower operational cost as compared to other reforming techniques.However,many pure metallic catalysts used in DRM face deactivation issues due to coke formation or sintering of the metal particles.A systematic search for highly efficient metallic catalysts,which reduce the reaction barriers for the rate-determining steps and resist carbon deposition,is urgently needed.Nickel is a typical low-cost transition metal for activating the C–H bond in methane.In this work,we applied a two-step workflow to search for nickel-based bimetallic catalysts with doping metals M(M-Ni)by combining density functional theory(DFT)calculations and machine learning(ML).We focus on the two critical steps in DRM—CH_(4) and CO_(2) direct activations.We used DFT and slab models for the Ni(111)facet to explore the relevant reaction pathways and constructed a data set containing structural and energetic information for representative M-Ni systems.We used this dataset to train ML models with chemical-knowledge-based features and predicted CH_(4) and CO_(2) dissociation energies and barriers,which revealed the composition–activity relationships of the bimetallic catalysts.We also used these models to rank the predicted catalytic performance of candidate systems to demonstrate the applicability of ML for catalyst screening.We emphasized that ML ranking models would be more valuable than regression models in high-throughput screenings.Finally,we used our trained model to screen 12 unexplored M-Ni systems and showed that the DFT-computed energies and barriers are very close to the ML-predicted values for top candidates,validating the robustness of the trained model.

关键词： Ni-based bimetallic catalysts dry reforming of methane syngas production CH_(4)and CO_(2)direct activations ranking model

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Seismic evaluation of the destress blasting efficiency

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第5期14卷 1501-1513页

作者： Krzysztof Fuławka Piotr Mertuszka Witold Pytel Marcin Szumny tristan Jones Research and Development Centre KGHM Cuprum Ltd.Wrocław53-659Poland Luossavaara-Kiirunavaara AB(LKAB) MalmbergetSE-98381Sweden

In this paper, selected methods of destress blasting efficiency assessment are presented, and novel quantitative methods based on in situ seismic measurements are proposed. The newly formulated solution combines two different approaches. The first, which is useful mostly for the near-field seismic analyses, is based on the analysis of seismic amplitude characteristics, and the second, relevant for farfield evaluation, is extended by the duration and frequency of the seismic wave. Both approaches are based on the seismic analyses of the waveforms generated by blasting recorded by the local seismic network. The proposed solutions are tested and validated in deep underground mines in Poland in which the room-and-pillar mining method is applied. Based on performed analysis, it is shown that both methods may be used as a rockburst hazard control in underground mines. However, developed methods may also be successfully implemented in other engineering practices, including the assessment of seismic vibrations in open pits and quarries.

关键词： Rockburst hazard Destress blasting Induced seismicity Seismic events Dominant frequency

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Dispersal syndrome and landscape fragmentation in the salt-marsh specialist spider Erigone longipalpis

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Current Zoology 2023年第1期69卷 21-31页

作者： Maxime Dahirel Marie Wullschleger tristan Berry Solène Croci Julien Pétillon Univ Rennes UR1CNRSEcosystèmesBiodiversitéÉvolution(ECOBIO)UMR 6553F-35000 RennesFrance Department of Biology Ghent UniversityB-9000 GhentBelgium Syndicat Mixte de Gestion des Milieux Naturels Réserve Naturelle Nationale de l’Étang NoirF-40510 SeignosseFrance CNRS Universitéde Rennes 2EPHE-PSLUniversitéd’AngersUniversitéde Bretagne OccidentaleUniversitéde Caen NormandieUniversitéde NantesUMR LETGF-35043 RennesFrance Institute for Coastal and Marine Research Nelson Mandela UniversityPort Elizabeth 6031South Africa

Dispersal and its evolution play a key role for population persistence in fragmented landscapes where habitat loss and fragmentation increase the cost of between-habitat movements.In such contexts,it is important to know how variation in dispersal and other traits is structured,and whether responses to landscape fragmentation are aligned with underlying dispersal-trait correlations,or dispersal syndromes.We,therefore,studied trait variation in Erigone longipalpis,a European spider species specialist of(often patchy)salt marshes.We collected spiders in two salt-marsh landscapes differing in habitat availability.We then reared lab-born spiders for two generations in controlled conditions,and measured dispersal and its association with various key traits.Erigone longipalpis population densities were lower in the more fragmented landscape.Despite this,we found no evidence of differences in dispersal,or any other trait we studied,between the two landscapes.While a dispersal syndrome was present at the among-individual level(dispersers were more fecund and faster growing,among others),there was no indication it was genetically driven:among-family differences in dispersal were not correlated with differences in other traits.Instead,we showed that the observed phenotypic covariations were mostly due to within-family correlations.We hypothesize that the dispersal syndrome is the result of asymmetric food access among siblings,leading to variation in development rates and carrying over to adult traits.Our results show we need to better understand the sources of dispersal variation and syndromes,especially when dispersal may evolve rapidly in response to environmental change.

关键词： context-dependent dispersal habitat loss Linyphiidae phenotypic correlations population density

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Local grid refinement in multigrid method for point contact problems of polycrystalline anisotropic material under dry and lubricated conditions

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Friction 2022年第12期10卷 2086-2110页

作者： Binbin ZHANG tristan G.VLOGMAN Predrag ANDRIC Ton C.BOR Cornelis H.VENNER Faculty of Engineering Technology University of TwenteEnschede 7500AEthe Netherlands SKF Research and Technology Development Houten 3992AEthe Netherlands

Predicting rolling bearing fatigue life requires knowledge of the three-dimensional(3D)stress fields in the roller and raceway near the lubricated contact.Owing to the increasingly severe operating conditions,the effect of localized features such as surface roughness,subsurface inclusions,and even the crystallographic structure of the material becomes important.Achieving such detail requires(locally)extremely dense gridding in simulations,which in 3D is a major challenge.Multigrid techniques have been demonstrated to be capable of solving such problems.In this study,multigrid techniques are shown to further increase the efficiency of the solution by exploiting local grid refinement while maintaining the simplicity of a uniform discretization.This is achieved by employing increasingly finer grids only locally,where the highest resolution is required.Results are presented for dry contact and elastohydrodynamically lubricated contact cases,circular as well as elliptic,with varying crystallographic structure,and with surface roughness.The results show that the developed algorithm is very well suited for detailed analysis,with also excellent prospects for computational diagnostics involving actual material crystallographic structure from electron backscatter diffraction measurements.

关键词： local grid refinement multigrid method polycrystalline anisotropic material dry and lubricated contact

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Productive and physiological implications of top-dress addition of branched-chain amino acids and arginine on lactating sows and offspring

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Journal of Animal Science and Biotechnology 2023年第3期14卷 1080-1101页

作者： Diana Luise Federico Correa Claudio Stefanelli Aude Simongiovanni tristan Chalvon-Demersay Maddalena Zini Luciano Fusco Paolo Bosi Paolo Trevisi Department of Agricultural and Food Sciences University of Bologna40127 BolognaItaly Department for Life Quality Studies Alma Mater StudiorumUniversity of Bologna47921 RiminiItaly Metex Noovistago 32 Rue Guersant75017 ParisFrance Department of Biomedical and Neuromotor Sciences Alma Mater StudiorumUniversity of Bologna40126 BolognaItaly Freelancer Reggio nell’EmiliaItaly.

Background Branched-chain amino acids(BCAAs),including L-leucine(L-Leu),L-isoleucine(L-Ile),L-valine(L-Val),and L-arginine(L-Arg),play a crucial role in mammary gland development,secretion of milk and regulation of the catabolic state and immune response of lactating sows.Furthermore,it has recently been suggested that free amino acids(AAs)can also act as microbial modulators.This study aimed at evaluating whether the supplementation of lactating sows with BCAAs(9,4.5 and 9 g/d/sow of L-Val,L-Ile and L-Leu,respectively)and/or L-Arg(22.5 g/d/sow),above the estimated nutritional requirement,could influence the physiological and immunological parameters,microbial profile,colostrum and milk composition and performance of sows and their offspring.Results At d 41,piglets born from the sows supplemented with the AAs were heavier(P=0.03).The BCAAs increased glucose and prolactin(P<0.05)in the sows’serum at d 27,tended to increase immunoglobulin A(IgA)and IgM in the colostrum(P=0.06),increased the IgA(P=0.004)in the milk at d 20 and tended to increase lymphocyte%in the sows’blood at d 27(P=0.07).Furthermore,the BCAAs tended to reduce the Chao1 and Shannon microbial indices(P<0.10)in the sows’faeces.The BCAA group was discriminated by Prevotellaceae_UCG-004,Erysipelatoclostridiaceae UCG-004,the Rikenellaceae_RC9_gut_group and Treponemaberlinense.Arginine reduced piglet mortality pre-(d 7,d 14)and post-weaning(d 41)(P<0.05).Furthermore,Arg increased the IgM in the sow serum at d 10(P=0.05),glucose and prolactin(P<0.05)in the sow serum at d 27 and the monocyte percentage in the piglet blood at d 27(P=0.025)and their jejunal expression of NFKB2(P=0.035)while it reduced the expression of GPX-2(P=0.024).The faecal microbiota of the sows in Arg group was discriminated by Bacteroidales.The combination of BCAAs and Arg tended to increase spermine at d 27(P=0.099),tended to increase the Igs(IgA and IgG,P<0.10)at d 20 in the milk,favoured the faecal colonisation of Oscillospiraceae UCG-005 and improved piglet growth.Conclusion Feedi

关键词： Microbiota Post-weaning mortality Prolactin Sows diet

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