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Setpoint Feasibility and Stability of Wind Park Control Interactions at Weak Grids

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Journal of Modern Power Systems and Clean Energy 2022年第6期10卷 1790-1796页

作者： Argüello Andrés IEEE the School of Electrical Engi‐neering and Computation University of CampinasCampinasBrazil

The controllers of wind parks that are connected to weak grids can induce unstable oscillations near the fundamental *** phenomenon can be studied with equivalent impedances of the wind generators,which depend on their operational setpoints at the fundamental *** feasibility of such setpoint,i.e.,solution to the power flow,does not depend on the control ***,oscillations from unfeasible setpoints and control instabilities both occur at weak grids and near the fundamental *** letter presents an exploratory study to map the conditions where both phenomena occur,using sensitivity studies comprising multiple setpoints and control parameter *** results are visually presented as the regions which inform the configurations leading to unfeasible setpoints,and unstable control interaction *** the results,it can be observed that the trajectory of the eigenvalues in the Nyquist plots towards an unfeasible setpoint approaches a fundamental frequency instability.

关键词： Control interaction impedance power quality resonance stability wind generator

Evolution of the 3.65-2.58 Ga Mairi Gneiss Complex,Brazil:Implications for growth of the continental crust in the São Francisco Craton

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Geoscience Frontiers 2022年第5期13卷 110-128页

作者： Igor de Camargo Moreira Elson Paiva Oliveira Daniel Francisco Martins de Sousa Institute of Geosciences University of Campinas(UNICAMP)CampinasSPBrazil

The composition and formation of the Earth’s primitive continental crust and mantle differentiation are key issues to understand and reconstruct the geodynamic terrestrial evolution,especially during the ***,the scarcity of exposure to these rocks,the complexity of lithological relationships,and the high degree of superimposed deformation,especially with long-lived magmatism,make it difficult to study ancient *** this complexity,exposures of the Archean Mairi Gneiss Complex basement unit in the São Francisco Craton offer important information about the evolution of South America’s primitive ***,here we present field relationships,LA-ICP-SFMS zircon U-Pb ages,and LA-ICP-MCMS Lu-Hf isotope data for the recently identified Eoarchean to Neoarchean gneisses of the Mairi *** Complex is composed of massive and banded gneisses with mafic members ranging from dioritic to tonalitic,and felsic members ranging from TTG(Tonalite-Trondhjemite-Granodiorite)to granitic *** new data point to several magmatic episodes in the formation of the Mairi Gneiss Complex:Eoarchean(ca.3.65–3.60 Ga),early Paleoarchean(ca.3.55–3.52 Ga),middle-late Paleoarchean(ca.3.49–3.33 Ga)and Neoarchean(ca.2.74–2.58 Ga),with no records of Mesoarchean ***-Hf data unveiled a progressive evolution of mantle differentiation and crustal recycling over *** the Eoarchean,rocks are probably formed by the interaction between the pre-existing crust and juvenile contribution from chondritic to weakly depleted mantle sources,whereas mantle depletion played a role in the Paleoarchean,followed by greater differentiation of the crust with thickening and recycling in the middle–late Paleoarchean.A different stage of crustal growth and recycling dominated the Neoarchean,probably owing to the thickening of the continental crust by collision,continental arc growth,and mantle differentiation.

关键词： São Francisco Craton Mairi Gneiss Complex Primitive continental crust Zircon U-Pb dating Lu-Hf isotope geochemistry

Analysis of the bounded and unbounded forms of USBM wettability index

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Energy Geoscience 2022年第1期3卷 94-102页

作者： Abouzar Mirzaei-Paiaman university of campinas(UNICAMP) CampinasSPBrazil

Understanding wettability is important in many processes where porous media and fluids are in *** *** of Mines(USBM)is one of the industry standard techniques for measuring *** index is calculated as USBM=lg(A_(1)/A_(2)),where A_(1) and A_(2) are the areas under capillary pressure curves of oil-drive and water-drive processes,***,the USBM is mistakenly assumed to vary over the range of-1 to 1 and compared with other *** this study we indicate that the lower and upper bounds of this index are not fully known in *** a result,comparison between USBM and other indices may cause erroneous interpretations due to dissimilar ranges of *** addition,even during examining the USBM of a sample it may not be possible to accurately interpret its *** highlight the bounded form of the USBM index(denoted as USBM^(*)=A_(1)-A_(2)/A_(1)+A_(2)),which varies over the range of -1 to 1,and suggest that it should replace the traditional form of USBM *** limestone coreplugs were collected from Asmari and Fahlian formations in two Iranian *** samples were used for performing primary imbibition relative permeability measurements,as well as primary imbibition and secondary drainage capillary pressure *** experiments are used to show the differences between USBM and USBM^(*)in comparative studies and compare them against other indices of Amott-Harvey,Lak and modified Lak.

关键词： Wettability Capillary pressure Relative permeability USBM USBM^(*)

Corrosion behavior of hypoeutectic Al-Cu alloys in H_2SO_4 and NaCl solutions

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Acta Metallurgica Sinica(English Letters) 2009年第4期22卷 241-246页

作者： Wislei R.Osório Leandro C.Peixoto Leonardo R.Garcia Amauri Garcia Department of Materials Engineering University of Campinas-UNICAMP

The aim of this work was to evaluate the electrochemical behaviour of hypoeutectic Al-Cu alloys immersed in two different solutions containing sulphate and chloride ions, respectively. The influence of Al2Cu associated to the dendritic arm spacing on the general corrosion resistance of such alloys is analysed. The typical microstructural pattern was examined by using scanning electron microscope. The corrosion tests were performed in both 0.5 M sulphuric acid and 0.5 M NaCl solutions at 25℃ by using an electrochemical impedance spectroscopy （EIS） technique and potentiodynamic polarization curves. Equivalent circuits by using the ZView software, were also used to provide quantitative support for the discussions. It was found that as the Cu content increased （i.e., increasing the Al2Cu fraction）, a higher susceptibility to the corrosion action in the NaCl solution is detected. In contrast, the tests carried out in the H2SO4 solution resulted in similar corrosion,rates for the three different hypoeutectic alloys.

关键词： Al-Cu alloys Al2Cu Corrosion Microstructure Castings

Use of graphs to assess well safety in drilling projects and during operations by identification of available barrier elements and consolidation of barrier envelopes

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Petroleum Research 2024年第3期9卷 418-431页

作者： Nelson Choueri Jr Marcelo Anunciacao Jaculli Amanda Gabriela Aparecida Silva Leite JoséRicardo Pelaquim Mendes university of campinas Brazil

Two independent barrier envelopes are the usual requirement used in most well operations to avoid catastrophic *** are classified as primary-concerning preventing the occurrence of a kick,and secondary-concerning controlling the kick to avoid a *** envelopes consist of barrier elements,thus verifying the quality of these elements is *** elements may be either redundant or mandatory,and these relationships are what constitute the barrier *** this work,we present a methodology to evaluate well safety by identifying existing barrier elements and barrier envelopes and mapping their relationships through the usage of graphs *** technique explicitly states the relationship between barriers and between them and *** enables a simpler visualization for well designers and allows the development of computer programs to control the safety and integrity of wells,both in the design phase and during drilling.12 graphs are provided for a 4-phase well(conductor,surface,production,and drill-in),considering both the primary and secondary *** for constructing each graph is thoroughly *** these graphs are used,reliability values can then be assigned to each barrier element,which results in the reliability of entire barrier *** can be further extended to analyze the safety of each operation by applying the system to operational sequences and even comparing well designs.

关键词： Barrier elements Barrier envelopes Well design Well safety Graphs technique

Clinical implications of single cell sequencing for bladder cancer

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Oncology Research 2024年第4期32卷 597-605页

作者： REZA YADOLLAHVANDMIANDOAB MEHRSA JALALIZADEH FRANCIELE APARECIDA VECHIA DIONATO KEINI BUOSI PATRÍCIA A.F.LEME LUCIANA S.B.DAL COL CRISTIANE F.GIACOMELLI ALEX DIAS ASSIS NASIM BASHIRICHELKASARI LEONARDO OLIVEIRA REIS UroScience School of Medical SciencesUniversity of CampinasUNICAMPCampinasSao Paulo13083-872Brazil ImmunOncology Pontifical Catholic University of CampinasPUC-CampinasCampinasSao Paulo13087-571Brazil

Bladder cancer(BC)is the 10th most common cancer worldwide,with about 0.5 million reported new cases and about 0.2 million deaths per *** this scoping review,we summarize the current evidence regarding the clinical implications of single-cell sequencing for bladder cancer based on PRISMA *** searched PubMed,CENTRAL,Embase,and supplemented with manual searches through the Scopus,and Web of Science for published studies until February *** included original studies that used at least one single-cell technology to study bladder ***-one publications were included in the ***-nine studies showed that this technology can identify cell subtypes in the tumor microenvironment that may predict prognosis or response to immune checkpoint inhibition *** studies were able to diagnose BC by identifying neoplastic cells through single-cell sequencing urine *** remaining studies were mainly a preclinical exploration of tumor microenvironment at single cell ***-cell sequencing technology can discriminate heterogeneity in bladder tumor cells and determine the key molecular properties that can lead to the discovery of novel perspectives on cancer *** nascent tool can advance the early diagnosis,prognosis judgment,and targeted therapy of bladder cancer.

关键词： Bladder cancer Urothelial carcinoma Transitional cell carcinoma Single-cell sequencing Tumor heterogeneity Immunotherapy Scoping review Tumor microenvironment

A High-Order Localized Artificial Diffusivity Scheme for Discontinuity Capturing on 1D Drift-Flux Models for Gas-Liquid Flows

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Advances in Applied Mathematics and Mechanics 2024年第1期16卷 47-74页

作者： Adyllyson H.Nascimento Eugenio S.Rosa Department of Energy School of Mechanical EngineeringUniversity of CampinasCampinasBrazil

A computational code is developed for the numerical solution of onedimensional transient gas-liquid flows using drift-flux models,in isothermal and also with phase change *** these two-phase models,classical upwind schemes such as Roe-and Godunov-type schemes are generally difficult to derive and expensive to use,since there are no treatable analytic expressions for the Jacobian matrix,eigenvalues and eigenvectors of the system of *** the other hand,the highorder compact finite difference scheme becomes an attractive alternative on these occasions,as it does not make use of any wave propagation information from the system of *** present paper extends the localized artificial diffusivity method for high-order compact finite difference schemes to solve two-phase flows with *** numerical method has simple formulation,straightforward implementation,low computational cost and,most importantly,*** numerical methodology proposed is validated by solving several numerical examples given in the *** simulations are sixth-order accurate and it is shown that the proposed numerical method provides accurate approximations of shock waves and contact *** is an essential property for simulations of realistic mass transport problems relevant to operations in the petroleum industry。

关键词： Compressible two-phase flows drift-flux model localized artificial diffusivity highorder numerical methods

Melting behavior and globular microstructure formation in semi-solid CoCrCuxFeNi high-entropy alloys

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Journal of Materials Science & Technology 2020年第17期52卷 207-217页

作者： Kaio Niitsu Campo Caio Chaussêde Freitas Leonardo Fanton Rubens Caram university of campinas School of Mechanical EngineeringSPBrazil

High-entropy alloys can be compelling raw materials for semi-solid *** the present study,the influence of the Cu content on the melting behavior and semi-solid microstructure of CoCrCuxFeNi(x=0,1,2,3)alloys was ***-melted samples were cross-rolled at room temperature and then isothermally treated at 1175℃in the semi-solid state for 300 *** characterization showed that the alloys containing Cu were formed by two fcc ***,the increase in Cu content also led to an increase in the volumetric fraction of the Cu-rich *** solidification,this phase,which is the last to form,nucleates and epitaxially grows on the Cu-lean *** the studied CoCrCuFeNi alloys exhibited the same melting *** Cu-rich phase melts at approximately 1120℃,whereas the Culean phase melts at approximately 1350℃,providing a suitable processing temperature range of more than 200℃.The semi-solid microstructures were considerably refined and globular regardless of the alloy composition,being suitable for semi-solid ***,each fcc phase exhibited roughly the same composition under the different processing *** Cu content in the Cu-lean phase was approximately 10 at.%,while Co,Cr,Fe,and Ni were in an approximately equiatomic ***,the Cu content was between 80 at.%and 86 at.%in the Cu-rich *** isothermal treatment of the CoCrCu3FeNi alloy at a higher temperature(1300℃)only caused the globules to *** conclusion,this work showed that these alloys can be potential candidates for semi-solid processing.

关键词： Semi-solid processing Thixoforming High-entropy alloys Microstructure

Non-exhaustive double effort test is reliable and estimates the firs ventilatory threshold intensity in running exercise

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Journal of Sport and Health Science 2018年第2期7卷 197-203页

作者： Lucas Dantas Maia Forte Fúlvia Barros Manchado-Gobatto Roberta Cunha Matheus Rodrigues Maria Ceclia Gallani Claudio Alexandre Gobatto School of Applied Science University of Campinas School of Nursing University of Campinas Faculty of Nursing Laval University

Purpose: The present study aimed to investigate the reliability of the non-exhaustive double effort(NEDE) test in running exercise and its associations with the ventilatory thresholds(VT_1 and VT_2) and the maximal lactate steady state(MLSS).Methods: Ten healthy male adults(age: 23 ± 4 years, height: 176.6 ± 6.4 cm, body mass: 76.6 ± 10.7 kg) performed 4 procedures:(1) a ramp test for VT_1 and VT_2 determinations measured by ratio of expired ventilation to O_2 uptake(VE/VO_2) and expired ventilation to CO_2 output(VE/VCO_2) equivalents, respectively;(2) the NEDE test measured by blood lactate concentration(NEDE_(LAC)) and heart rate responses(NEDE_(HR));(3) a retest of NEDE for reliability analysis; and(4) continuous efforts to determine the MLSS intensity. The NEDE test consisted of4 sessions at different running intensities. Each session was characterized by double efforts at the same running velocity(E1 and E2, 180 s), separated by a passive recovery period(90 s rest). LAC and HR values after E1 and E2(in 4 sessions) were used to estimate the intensity equivalent to"null delta" by linear fit. This parameter represents, theoretically, the intensity equivalent to maximal aerobic ***: The intraclass correlation coefficient indicated significant reliability for NEDE_(LAC)(0.93) and NEDE_(HR)(0.79)(both p < 0.05). There were significant correlations, no differences, and strong agreement with the intensities predicted by NEDE_(LAC)(10.1 ± 1.9 km/h) and NEDE_(HR)(9.8 ± 2.0 km/h) to VT_1(10.2 ± 1.1 km/h). In addition, despite significantly lower MLSS intensity(12.2 ± 1.2 km/h), NEDE_(LAC) and NEDE_(HR) intensities were highly correlated with this parameter(0.90 and 0.88, respectively).Conclusion: The NEDE test applied to running exercise is reliable and estimates the VT_1 intensity. Additionally, NEDE intensities were lower but still correlated with VT_2 and MLSS.

关键词： Aerobic exercise Anaerobic threshold Maximal lactate steady state Non-exhaustive protocol Training prescription Ventilatory threshold