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Modeling slow deformation of polygonal particles using DEM

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Particuology 2008年第6期6卷 506-514页

作者： Andrés A. pea pedro G. Lind Hans J. Herrmann Institute for Computational Physics Universitt Stuttgart Computational Physics IfB HIF E12 ETH Hnggerberg CH-8093 Zrich Switzerland Departamento de Física Universidade Federal do Ceará

We introduce two improvements in the numerical scheme to simulate collision and slow shearing of irregular particles. First, we propose an alternative approach based on simple relations to compute the frictional contact forces. The approach improves efficiency and accuracy of the Discrete Element Method （DEM） when modeling the dynamics of the granular packing. We determine the proper upper limit for the integration step in the standard numerical scheme using a wide range of material parameters. To this end, we study the kinetic energy decay in a stress controlled test between two particles. Second, we show that the usual way of defining the contact plane between two polygonal particles is, in general, not unique which leads to discontinuities in the direction of the contact plane while particles move. To solve this drawback, we introduce an accurate definition for the contact plane based on the shape of the overlap area between touching particles, which evolves continuously in time.

关键词： Granular media Discrete element method Slow deformation Contact forces

Super pathogens from environmental biotechnologies threaten global health

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National Science Review 2021年第9期8卷 20-22页

作者： Yong Xiao Feng Zhao Josep pe?uelas Qiansheng Huang Yong-Guan Zhu CAS Key Laboratory of Urban Pollutant Conversion Institute of Urban Environment Chinese Academy of Sciences CSIC Global Ecology Unit CREAF-CSIC-UAB CREAF Autonomous University of Barcelona CAS Key Laboratory of Urban Environment and Health Institute of Urban Environment Chinese Academy of Sciences State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences

Microbial pathogens are viruses, bacteria, fungi and protozoa infecting humans,animals or plants. Super pathogens (also known as superbugs) able to resist multiple antimicrobials and cause fatal infections have been increasingly considered an emerging threat to global health [1].The COVID-19 pandemic has caused more than 3.8 million deaths as of 15 June2021, reminding us that we should always be alert to the next pandemic caused by super pathogens. We know little, however, about the origin and transmission of super pathogens in the *** the various potential sources of super pathogens, special attention should be paid to environmental biotechnologies (EBTs) for treating wastewater.

关键词： GENES

Effect of calcination temperature on structural properties and catalytic activity in oxidation reactions of LaNiO_3 perovskite prepared by pechini method

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Journal of Rare Earths 2012年第3期30卷 210-216页

作者： K. Rida M.A. pea E. Sastre A. Martínez-Arias Laboratory for the Study of Interactions Between Materials and Their Environment University of Jijel Institute of Catalysis and petroleum-Chemistry CSIC C/Marie Curie 2 Campus de Cantoblanco 28049 Madrid Spain

The study presented the preparation of the perovskite oxide LaNiO3 by the complex citrate method, paying particular attention to evolution of its formation from the amorphous precursor with varied calcination temperatures. The products obtained after heat treatment under air between 200 and 800 ℃ were characterized by X-ray diffraction （XRD）, thermogravimetric and differential thermal analysis （TG-DTA）, Fourier transform infrared spectroscopy （FTIR）, SBET measurements and X-ray photoelectron spectroscopy （XPS）. The results showed the formation of a single phase with perovskite structure from ca. 550 ℃. Tests on the two catalytic oxidation reactions of C3H6 and CO over the system calcined between mentioned temperatures were examined on the basis of characterization results and showed that optimum catalytic properties for such reactions were achieved for the perovskite calcined at 600 ℃. In turn, correlations between redox and catalytic properties were established on the basis of thermogravimetric temperature programmed reduction （TPR） analysis.

关键词： LaNiO3 perovskite pechini SOFC C3H6 and CO combustion rare earths

Recognition of Human Actions through Speech or Voice Using Machine Learning Techniques

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Computers, Materials & Continua 2023年第11期77卷 1873-1891页

作者： Oscar peña-Cáceres Henry Silva-Marchan Manuela Albert Miriam Gil Professional School of Systems Engineering Universidad César VallejoPiura20009Perú Escola Tècnica Superior d’Enginyeria Departament d’InformàticaUniversitat de ValènciaBurjassotValencia46100Spain Department of Mathematics Statistics and InformaticsUniversidad Nacional de TumbesTumbes24000Perú Valencian Research Institute for Artificial Intelligence Universitat Politècnica de ValènciaValencia46022Spain

The development of artificial intelligence(AI)and smart home technologies has driven the need for speech recognition-based *** demand stems from the quest for more intuitive and natural interaction between users and smart devices in their *** recognition allows users to control devices and perform everyday actions through spoken commands,eliminating the need for physical interfaces or touch screens and enabling specific tasks such as turning on or off the light,heating,or lowering the *** purpose of this study is to develop a speech-based classification model for recognizing human actions in the smart *** seeks to demonstrate the effectiveness and feasibility of using machine learning techniques in predicting categories,subcategories,and actions from sentences.A dataset labeled with relevant information about categories,subcategories,and actions related to human actions in the smart home is *** methodology uses machine learning techniques implemented in Python,extracting features using CountVectorizer to convert sentences into numerical *** results show that the classification model is able to accurately predict categories,subcategories,and actions based on sentences,with 82.99%accuracy for category,76.19%accuracy for subcategory,and 90.28%accuracy for *** study concludes that using machine learning techniques is effective for recognizing and classifying human actions in the smart home,supporting its feasibility in various scenarios and opening new possibilities for advanced natural language processing systems in the field of AI and smart homes.

关键词： AI machine learning smart home human action recognition

Evaluation of biostimulation and Tween 80 addition for the bioremediation of long-term DDT-contaminated soil

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Journal of Environmental Sciences 2015年第2期27卷 101-109页

作者： Bibiana Betancur-Corredor Nancy J.Pino Santiago Cardona Gustavo A.peuela GDCON Research Group Faculty of Engineering University Research Headquarters (SIU) University of Antioquia School of Geosciences and Environment Faculty of Mines National University of Colombia School of Microbiology University of Antioquia

The bioremediation of a long-term contaminated soil through biostimulation and surfactant addition was evaluated. The concentrations of 1,1,1-trichloro-2,2-bis（4-chlorophenyl）ethane（DDT） and its metabolites 1,1-dichloro-2,2-bis（4-chlorophenyl） ethane（DDD） and1,1-dichloro-2,2-bis（4-chlorophenyl） ethylene（DDE） were monitored during an 8-week remediation process. Physicochemical characterization of the treated soil was performed before and after the bioremediation process. The isolation and identification of predominant microorganisms during the remediation process were also carried out. The efficiency of detoxification was evaluated after each bioremediation protocol. Humidity and p H and the heterotrophic microorganism count were monitored weekly. The DDT concentration was reduced by 79% after 8 weeks via biostimulation with surfactant addition（B ＋ S） and 94.3%via biostimulation alone（B）. Likewise, the concentrations of the metabolites DDE and DDD were reduced to levels below the quantification limits. The microorganisms isolated during bioremediation were identified as Bacillus thuringiensis, Flavobacterium sp., Cuprivadius sp.,Variovorax soli, Phenylobacterium sp. and Lysobacter sp., among others. Analysis with scanning electron microscopy（SEM） allowed visualization of the colonization patterns of soil particles. The toxicity of the soil before and after bioremediation was evaluated using Vibrio fischeri as a bioluminescent sensor. A decrease in the toxic potential of the soil was verified by the increase of the concentration/effect relationship EC50 to 26.9% and 27.2% for B ＋ S and B, respectively, compared to 0.4% obtained for the soil before treatment and 2.5%by natural attenuation after 8 weeks of treatment.

关键词： DDT Soil Bioremediation Biostimulation Surfactant Toxicity

Conditioning of a Calcaric Soil with Biosolid and Compost Under Laboratory Conditions: Exploration of Soil Property Evolution

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pedosphere 2019年第2期29卷 266-272页

作者： José Antonio GALáN-PéREZ Aránzazu pe?A Andalusian Institute for Earth Sciences Spanish National Research Council-University of Granada (CSIC-UGR)

Dear Editor,Conditioning of soils of low organic carbon(OC)is essential to establish optimal fertility conditions for the growth and development of future crops.A usual practice is the substrates of various origins,among which cheap wastes from agricultural or urban residues with high organic matter(OM)content have been gaining popularity in the last *** increase in soil OM is considered a desirable trait in agriculture because of its benefits.

关键词： Exploration Conditioning Laboratory

The challenges of sequestering terrestrial carbon

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National Science Review 2022年第8期 9-10页

作者： Josep pe?uelas Center for Ecological Research and Forestry Applications(CREAF) Global Ecology Unit CREAF-CSIC-UAB Spanish National Research Council(CSIC)

Nature may become a powerful ally in tackling climate *** is growing that ‘nature-based climatic solutions’(Nb CS) can help us to transition toward a society with zero net emissions and thus protect us from climate change and its consequent impacts while supporting biodiversity and securing ecosystem services. The actual potential of Nb CS to provide the intended benefits, however, has not been rigorously assessed.

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Partition of Forecast Error into Positional and Structural Components

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Advances in Atmospheric Sciences 2021年第6期38卷 1012-1019页

作者： Isidora JANKOV Scott GREGORY Sai RAVELA Zoltan TOTH Malaquías peÑA Global Systems Laboratory NOAA/OARBoulderCO 80305USA General Atomics Electromagnetic Systems GroupLongmontCO 80501USA Earth Signals and Systems Group EarthAtmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMA 02139USA Department of Civil and Environmental Engineering University of Connecticut StorrsCT 06269USA

Weather manifests in spatiotemporally coherent *** forecasts hence are affected by both positional and structural or amplitude *** has been long recognized by practicing forecasters(cf.,e.g.,Tropical Cyclone track and intensity errors).Despite the emergence in recent decades of various objective methods for the diagnosis of positional forecast errors,most routine verification or statistical post-processing methods implicitly assume that forecasts have no positional *** Forecast Error Decomposition(FED)method proposed in this study uses the Field Alignment technique which aligns a gridded forecast with its verifying analysis *** total error is then partitioned into three orthogonal components:(a)large scale positional,(b)large scale structural,and(c)small scale error *** use of FED is demonstrated over a month-long MSLP data *** expected,positional errors are often characterized by dipole patterns related to the displacement of features,while structural errors appear with single extrema,indicative of magnitude *** most important result of this study is that over the test period,more than 50%of the total mean sea level pressure forecast error variance is associated with large scale positional *** importance of positional error in forecasts of other variables and over different time periods remain to be explored.

关键词： forecast error orthogonal decomposition positional structural

Architectural typology of rural housing in Jaen,peru

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Built Heritage 2022年第1期6卷 76-93页

作者： Floiran peÑa-Huaman Diego Sifuentes-Rivera Cristian Yarasca-Aybar Escuela Profesional de Arquitectura Universidad Peruana UnionLimaPeru

Jaén is one of the most important cities in the northern highlands of peru due to its strategic location,commerce,and agricultural ***én has more than 185 thousand inhabitants,of which 48%live in rural areas,representing approximately 31 thousand rural *** research aims to determine the types of rural housing in Jaen,showing the possible variations and architectural manifestations due to the territorial and cultural characteristics.A field observation sheet has been used to study the rural dwellings of populated centres previously classified by altitudinal *** results show six architectural types of rural housing classified into two groups:"rural-residential housing"and"rural-agricultural housing"'These architectural types are generally located near water sources,within agricultural plots,and on *** architectural program is characterised by agricultural activity and family composition,which has grown over *** most commonly used construction systems are"pirca"and"quincha"',using natural materials such as"ichu"and *** is also evidence of cultural traditions rooted in the construction,such as"cambio de fuerzas""paracaico",and"minga".Therefore,the relevance of Jaen's rural housing is its geographical reading of the territory through the architectural and cultural legacy of these buildings.

关键词： Architectural typologies peru Rural architecture Vernacular architecture Rural housing