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Generic Modeling and Control Framework for Power Systems dominated by Power Converters Connected Through a Passive Transmission and distribution Grid

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 292-301页

作者： Qing-Chang Zhong marcio Stefanello department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA Syndem LLC USA.M.Stefanello is with the Fundacao Universidade Federal do Pampa at AlegreteRS97546-550Brazil

In this paper,a compact mathematical model having an elegant structure,together with a generic control framework,are proposed for generic power systems dominated by power converters that are interconnected through a passive transmission and distribution(T&d)grid,by adopting the port-Hamiltonian(pH)systems theory and the fundamental circuit theory.The models of generic T&d lines are developed and then the model of a generic T&d grid is established.With the proposed control framework,the controlled converters are proven to be passive and Input-to-State Stable(ISS).The compact mathematical model is scalable and can be applied to power systems with multiple power electronic converters with generic passive controllers,passive local loads,and different types of passive T&d lines connected in a meshed configuration without self-loops,so it is very generic.Moreover,the resulting power system is proven to be ISS as well.The analysis is carried out without assumptions on constant frequency/voltage,constant loads,and/or lossless networks,except the need of passivity for all parts involved,and without using the Clarke/Park transformations or the graph theory.To simplify the presentation,three-phase balanced systems are adopted but the results can be easily adapted for single-phase or unbalanced three-phase systems.

关键词： Input-to-State Stable(ISS) passivity,portHamiltonian(pH)systems Power electronic converters dominated power systems Synchronized and democratized(SYNdEM)grid architecture

Transarterial embolization is an acceptable bridging therapy to hepatocellular carcinoma prior to liver transplantation

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World Journal of Transplantation 2024年第2期14卷 126-134页

作者： Gabriel Lazzarotto-da-Silva Leandro A Scaffaro Mauricio Farenzena Lucas Prediger Rafaela K Silva Flávia Heinz Feier Tomaz J M Grezzana-Filho Pablo d Rodrigues Alexandre de Araujo Mario Reis Alvares-da-Silva Roberta C Marchiori Cleber Rosito Pinto Kruel marcio Fernandes Chedid department of Liver Transplant and Hepatobiliary Surgery Unit Hospital de Clínicas de Porto AlegrePorto Alegre 90035-007Brazil department of Interventional Radiology Unit Hospital de Clínicas de Porto AlegrePorto Alegre 90035-007Brazil department of Gastroenterology and Hepatology Hospital de Clínicas de Porto AlegrePorto Alegre 90035-007Brazil

BACKGROUNd Hepatocellular carcinoma(HCC)is an aggressive malignant neoplasm that requires liver transplantation(LT).despite patients with HCC being prioritized by most organ allocation systems worldwide,they still have to wait for long periods.Locoregional therapies(LRTs)are employed as bridging therapies in patients with HCC awaiting LT.Although largely used in the past,transarterial embolization(TAE)has been replaced by transarterial chemoembolization(TACE).However,the superiority of TACE over TAE has not been consistently shown in the literature.AIM To compare the outcomes of TACE and TAE in patients with HCC awaiting LT.METHOdS All consecutive patients with HCC awaiting LT between 2011 and 2020 at a single center were included.All patients underwent LRT with either TACE or TAE.Some patients also underwent percutaneous ethanol injection(PEI),concom-itantly or in different treatment sessions.The choice of LRT for each HCC nodule was determined by a multidisciplinary consensus.The primary outcome was waitlist dropout due to tumor progression,and the secondary outcome was the occurrence of adverse events.In the subset of patients who underwent LT,complete pathological response and post-transplant recurrence-free survival were also assessed.RESULTS Twelve(18.5%)patients in the TACE group(only TACE and TACE+PEI;n=65)and 3(7.9%)patients in the TAE group(only TAE and TAE+PEI;n=38)dropped out of the waitlist due to tumor progression(P log-rank test=0.29).Adverse events occurred in 8(12.3%)and 2(5.3%)patients in the TACE and TAE groups,respectively(P=0.316).Forty-eight(73.8%)of the 65 patients in the TACE group and 29(76.3%)of the 38 patients in the TAE group underwent LT(P=0.818).Among these patients,complete pathological response was detected in 7(14.6%)and 9(31%)patients in the TACE and TAE groups,respectively(P=0.145).Post-LT,HCC recurred in 9(18.8%)and 4(13.8%)patients in the TACE and TAE groups,respectively(P=0.756).Posttransplant recurrence-free survival was similar between the groups(P log-rank test=0.71).CONCL

关键词： Hepatocellular carcinoma Transarterial embolization Transarterial chemoembolization Liver transplantation Locoregional therapy Bridging

Pseudo-discontinuum model to simulate hard-rock mine pillars

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Underground Space 2023年第4期11卷 81-95页

作者： Erick Ro genes Alessandra dos Santos Gomes marcio Muniz de Farias Leandro Lima Rasmussen Faculty of Technology University of BrasiliaDF 70910-900BrasiliaBrazil

In this study,the pseudo-discontinuum modeling technique,called continuum Voronoi block model(CVBM),was applied to repre-sent the behavior of hard-rock pillars from underground mines subjected to high field stresses.The CVBM’s ability to produce numerical results consistent with the observed behavior of pillars is demonstrated through the numerical analysis of a hypothetical case and a back analysis of the Creighton mine pillar.The results show that the model can capture convergence displacements and explicitly show the formation of macro-fractures parallel to excavation walls,intact rock slabs,and V-shaped notches.These components are characteristics of brittle failure induced by highly stressed ground conditions.The studies presented in this work confirm the CVBM as a convenient tool for the numerical modeling of intact rock pillars excavated in deep underground mines.

关键词： Brittle failure Spalling Bulking Voronoi tessellation

A multivariate analysis on spatiotemporal evolution of Covid-19 in Brazil

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Infectious disease Modelling 2020年第1期5卷 670-680页

作者： marcio Luis Ferreira Nascimento Ph.d. Nano Group@UFBA Department of Chemical EngineeringPolytechnic SchoolFederal University of BahiaRua Aristides Novis 2Federação40210-630SalvadorBABrazil PEI-Graduate Program in Industrial Engineering Department of Chemical EngineeringPolytechnic SchoolFederal University of BahiaRua Aristides Novis 2Federação40210-630SalvadorBABrazil

This data-driven work aims to analyze and classify the spatiotemporal distribution of all Brazilian states considering data so diverse as the number of Covid-19 cases,deaths,confirmed cases per 100 k inhabitants,mortality per 100 k inhabitants and case fatality rates as health indicators.We also considered population,area and population density as geographic indicators.Finally,GdP and HdI were taken into account as economic and social criteria.For this task data were collected from April 3rd until August 8th,2020,corresponding to epidemiological weeks 14e32,reaching three million cases and a hundred thousand deaths.With this data it was possible to classify Brazilian states using multivariate methods into possible groups by means of non-hierarchical(k-means)cluster as well as factor analysis.It was possible to group all states plus the Federal district into five clusters,taking into account these 10 variables over the first five months of the epidemic.Group changes between states were observed over time and clusters,and between three and four factors were found.However,even with great difference on health indicators during days,the number of clusters remains fixed.Also,S^ao Paulo and Rio de Janeiro states were ranked at top list taking into account all epidemiological weeks.Correlations were observed between variables,such as the number of Covid cases and deaths with GdP for most of epidemiological weeks.Some clusters were more critical due to specific variables,including cities that are main hotspots.These multivariate findings would provide a comprehensive description of the ongoing Covid-19 epidemic and may help to guide subsequent studies to understand and control virus transmission.

关键词： Pandemic COVId-19 Coronavirus K-means clustering Factor analysis Spatiotemporal analysis

Risk factors, surgical complications and graft survival in liver transplant recipients with early allograft dysfunction

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Hepatobiliary & Pancreatic diseases International 2019年第5期18卷 423-429页

作者： douglas Bastos-Neves Paolo Rogerio de Oliveira Salvalaggio marcio dias de Almeida digestive and Hepatobiliary Surgery Hospital Sao Vicente de PauloRio de JaneiroBrazil Liver Transplant Unit Hospital Israelita Albert EinsteinSao PauloBrazil

Background: Early allograft dysfunction (EAd) is a severe complication after liver transplantation. The associated risk factors and complications have re-gained recent interest. This study investigated risk factors, survival and complications associated with EAd in a large liver transplant center in Latin America. Methods: Retrospective, unicenter, cohort, based on data from adult patients undergoing first deceaseddonor liver transplant from January 2009 to december 2013. EAd was defined by one or more of the following:(i) bilirubin ≥10 mg/dL on postoperative day 7;(ii) international normalized ratio ≥1.6 on postoperative day 7, and (iii) alanine aminotransferase or aspartate aminotransferase > 2000 IU/L within the first seven days after transplant. Results: A total of 602 patients were included;of these 34.2% developed EAd. donor risk factors were male ( P = 0.007), age between 50 and 59 years ( P = 0.034), overweight ( P = 0.028) or grade I obesity ( P = 0.012), sodium > 157 mmol/L ( P = 0.002) and grade IV ischemia/reperfusion injury ( P = 0.002). Cold ischemia time ≥10 h ( P = 0.008) and warm ischemia time ≥40 min ( P = 0.013) were the surgical factors. Male ( P d with the non-EAd group, patients with EAd were submitted to more reoperations (24.3% vs. 13.4%, P = 0.001) and had higher graft loss rates (37.9% vs. 21.2%, P d risk factors are related to donor, surgical procedure and recipient. donor risk factors for EAd were male, age between 50 and 59 years, donor overweight or grade Ⅰ obesity, sodium > 157 mmol/L and grade Ⅳ ischemia/reperfusion injury. Cold ischemia time ≥10 h and warm ischemia time ≥40 min were the surgical risk factors. Male was the only recipient protective factor. Patients with EAd had higher reoperations and graft loss rates.

关键词： Graft survival Liver transplantation Primary graft dysfunction donor evaluation

Historical relationships of areas of endemism of the Brazilian Atlantic rain forest： a cladistic biogeographic analysis of harvestman taxa （Arachnida： Opiliones）

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Current Zoology 2017年第5期63卷 525-535页

作者： marcio B. dASILVA Ricardo PINTO-dA-ROCHA Juan J. MORRONE departamento de Sistematica e Ecologia CCEN Universidade Federal da Paraiba Cidade Universitaria Joao Pessoa PB Brazil departamento de Zoologia Instituto de Biociencias Universidade de Sao Paulo Sao Paulo SP Brazil Museo de Zoologia "Alfonso L. Herrera" Departamento de Biologia Evolutiva Facultad de Ciencias Universidad Nacional Autdnoma de Mexice (UNAM) 04510 Mexico City Mexico

Based on a cladistic biogeographic analysis of 6 species-level phylogenies of harvestman taxa, wesearched for congruence in the historical relationships of 12 areas of endemism of the BrazilianAtlantic Rain Forest. We constructed general area cladograms using Primary Brooks ParsimonyAnaJysis （BPA）, BPA of nodes, and paralogy-free subtree analysis. These analyses resulted in 6general area cladograms, that allow to infer a general pattern of the relationships among areas ofendemism from the Brazilian Atlantic Rain Forest. Northern areas resulted related basally showingmain disjunctions at the doce River Valley and Todos os Santos Bay/S^o Francisco River Valley.The remaining areas of endemism were included in a southern and a southeastern block, sepa-rated by the Ribeira do Iguape Valley. Incongruence Length differences tests showed no significantincongruence among the resulting cladograms and other matrix partitions. We concluded that tec-tonism and ancient marine transgressions were the probable processes responsible for the maindisjunctions, whereas Neogene refugia seem to have caused the more recent disjunctions. Thegeneral pattern and redundancy in area relationships suggest a model of main reiterative barriersin diversification at multiple times for the evolution of the Atlantic Rain Forest. The renewal of cla-distic biogeography and the search for common biogeographic patterns are discussed.

关键词： dispersal, historical biogeography, Mata Atlantica, speciation, vicariance.

A comparative study for the performance of encased granular columns

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第2期11卷 379-388页

作者： Iman Hosseinpour Cristian Soriano marcio S.S.Almeida department of Civil Engineering Faculty of EngineeringThe University of Guilan Graduate School in Research and Engineering (COPPE) Federal University of Rio de Janeiro (UFRJ)

This paper describes a three-dimensional(3d) numerical analysis of a test embankment on geotextileencased columns(GECs), in comparison with two-dimensional(2d) axisymmetric and plane strain analyses. The 3d numerical analysis was performed considering a rectangular strip under the embankment centerline. The 2d analysis was also carried out using axisymmetric unit cell and plane strain approaches.Numerical results indicated that the adopted 3d strip model represented well the measured deformations and pore pressure evolution during embankment construction and post-contraction periods.Unlike the unit cell model, both plane strain and 3d analyses could properly determine the settlement profile along the embankment base as well as the profile of the horizontal soil deformation beneath the embankment toes. The plane strain analysis, however, was not able to compute the geotextile ring force which might be simply calculated using the axisymmetric unit cell approach. The paper also showed that, due to horizontal boundary fixities applied to the embankment borders, the unit cell model clearly underestimated the tension developed in the basal geogrid.

关键词： Soft soil Embankment Encased columns Geosynthetic Numerical analysis

The occlusal plane in the facial context:inter-operator repeatability of a new three-dimensional method

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International Journal of Oral Science 2012年第1期4卷 34-37页

作者： Riccardo Rosati Alberto Rossetti marcio de Menezes Virgilio F Ferrario Chiarella Sforza department of Human Morphology Universita` degli Studi di MilanoMilano 20133Italy

The repeatability of a non-invasive digital protocol proposed to evaluate the three-dimensional（3d） position of the occlusal plane in the face is assessed.dental virtual models and soft tissue facial morphology of 20 adult subjects were digitally integrated using a 3d stereophotogrammetric imaging system.The digital 3d coordinates of facial and dental landmarks were obtained by two different operators.Camper＇s（facial） and occlusal（dental） planes were individuated,and their 3d relationships were measured.The repeatability of the protocol was investigated and showed no significant differences in repeated digitizations.The angle between occlusal and Camper＇s planes was smaller than 26 in the frontal and horizontal projections.In the sagittal projection,the angle was observed to be,on average,4.9 6.The determined occlusal plane pitch,roll and yaw values show good agreement with previously published data obtained by different protocols.The current non-invasive method was repeatable,without inter-operator differences and can facilitate assessment of healthy subjects.

关键词： healthy subjects occlusal plane stereophotogrammetry three-dimensional analysis

Critical state model for structured soil

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 630-641页

作者： Cristhian Mendoza marcio Muniz de Farias department of Civil Engineering Universidad Nacional de Colombia Sede ManizalesManizalesColombia department of Civil and Environmental Engineering University of BrasiliaBrasiliaDFBrazil

Structure is an evident determinant for macroscopic behaviors of soils.However,this is not taken into account in most constitutive models,as structure is a rather complex issue in models.For this,it is important to develop and implement simple models that can reflect this important aspect of soil behavior.This paper tried to model structured soils based on well-established concepts,such as critical state and sub-loading.Critical state is the core of the classic Cam Clay model.The sub-loading concept implies adoption of an inner(sub-loading)yield surface,according to specific hardening rules for some internal strain-like state variables.Nakai and co-workers proposed such internal variables for controlling density(p)and structure(ω),using a modified stress space,called tij.Herein,similar variables are used in the context of the better-known invariants(p and q)of the Cam Clay model.This change requires explicit adoption of a non-associated flow rule for the sub-loading surface.This is accomplished by modifying the dilatancy ratio of the Cam Clay model,as a function of the new internal variables.These modifications are described and implemented under three-dimensional(3d)conditions.The model is then applied to simulating laboratory tests under different stress paths and the results are compared to experiments reported for different types of structured soils.The good agreements show the capacity and potential of the proposed model.

关键词： Elastoplasticity Cam clay with sub-loading Structured soil Tropical soil Non-associated flow rule