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Building Simulation 2021年第4期14卷 945-967页

作者： gian Luca Brunetti Politecnico di Milano Department of Architecture and Urban Studies(DAStU)via Bonardi 320133MilanoItaly

The ability to take into account reflections from obstructions is of fundamental importance in building energy simulation (BES), because reflections can have a substantial influence on solar gains. In BES tools, this ability is often implemented duplicating functionalities that have already been solved efficiently in lighting simulation tools. This happens because importing those functionalities from a lighting simulation tool (source) into a BES tool (target) is usually a complex operation producing non-portable results. This article demonstrates that this ability can be imported modularly and portably without intervening in the internals of the two tools. This can be obtained by: (1) creating, in the source tool, pairs of models which are analogue-on the one hand-to the original model in the target tool, and-on the other hand-to the model in the target tool hypothetically enriched with some predictive ability only available in the source tool;(2) measuring, at each time step, the ratio between the performances predicted by the source tool as regards the two analogue models;(3) re-scaling, at each time-step, the performance predicted by the target tool on the basis of that ratio. When appropriate analogue models are utilized, this strategy enables distinct simulation tools to work like an integrated computing unit.

关键词： irradiance ratios shading factors analogue models solar reflections insolation factors

Optimal weakening and damping using polynomial control for seismically excited nonlinear structures

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Earthquake Engineering and Engineering Vibration 2009年第4期8卷 607-616页

作者： gian Paolo Cimellaro Department of Structural & Geotechnical Engineering(DISTR)

This paper presents an approach for the optimal design of a new retrofit technique called weakening and damping that is valid for civil engineering inelastic structures. An alternative design methodology is developed with respect to the existing ones that is able to determine the locations and the magnitude of weakening and/or softening of structural elements and adding damping while insuring structural stability. An optimal polynomial controller that is a summation of polynomials in nonlinear states is used in Phase I of the method to reduce the peak response quantities of seismically excited nonlinear or hysteretic systems. The main advantage of the optimal polynomial controller is that it is able to automatically stabilize the structural system. The optimal design of a shear-type structure is used as an example to illustrate the feasibility of the proposed approach, which leads to a reduction of both peak inter-story drifts and peak total accelerations.

关键词： weakening and damping optimal design optimal polynomial controller inter-story drift acceleration

A new approach to the design of surface subsystems of polymeric insulators for HV and MV apparatus under AC voltage

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High Voltage 2023年第4期8卷 651-658页

作者： gian Carlo Montanari Debasish Nath Pasquale Cambareri Center for Advanced Power Systems Florida State UniversityTallahasseeFloridaUSA Dipartimento di Elettronica Informazione e BioingegneriaPolitecnico di MilanoMilanoItaly

The design of high voltage and medium voltage AC and DC standoff insulators,and,in general,of insulation systems where surface and interface properties are predominant factors,is based on specifications and standards that rely upon long-term experiences and lab *** insulating properties depend on electrical and thermal stresses,besides environmental factors,and the inception of extrinsic ageing phenomena,such as partial discharges,can be already a cause of reduced reliability and premature failure(for organic insulating materials).An innovative approach,based on field simulation,discharge modelling,and partial discharge inception measurements is presented by the authors,which can establish a solid basis to optimise insulation design for any type of supply voltage *** method,the three-leg approach,is applied here to a cable system under AC sinusoidal voltage,but it can work for any type of insulation system,such as bushings,switch gears,transformers,rotating machines,and power electronics boards.

关键词： insulation approach insulator

An innovative approach to partial discharge measurement and analysis in DC insulation systems during voltage transient and in steady state

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High Voltage 2021年第4期6卷 565-575页

作者： gian Carlo Montanari Riddhi Ghosh Center for Advanced Power Systems Florida State UniversityTallahasseeFloridaUSA

Measuring partial discharges in DC insulation systems is an issue due to the lack of a reference relating the voltage waveform to the physics of discharge ***,DC is not always steady state,due to voltage and load transients that generate electric field profile variations inside an insulation system,which can affect partial discharge inception likelihood and *** discharge measurement technology must be able to separate discharge pulses from noise and identify the type of sources generating partial discharge,which is related to condition assessment and ***,measurement and analysis should be automatic and unsupervised,in order to get rid,partially or totally,of expert *** study addresses a new approach to partial discharge measurements in DC insulation systems,presenting algorithms for separation,recognition and identification,which are effective both in DC steady state and during voltage(and load)*** algorithms are automatic and do not require expert *** cases of algorithm application on test objects consisting of multilayer polymeric specimens with an internal cavity and defective cable models are presented and *** effectiveness is proved,at least at a laboratory level,with effective noise separation and identification of discharge typology.

关键词： insulation state separation

Renewed considerations on the utility(or the futility)of hepatic resections for breast cancer liver metastases

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Hepatobiliary Surgery and Nutrition 2021年第1期10卷 49-58页

作者： gian Luca Grazi Hepatobiliary Biliary Pancreatic Surgery IRCCS Regina Elena National Cancer InstituteRomeItaly

Importance:Indication for liver resection(LR)for localized hepatic metastases from breast cancer(BC)is still a matter of ***:A literature review of recent scientific papers pertaining to hepatectomies for BC liver metastases(LM).Evidence Review:We based our systematic review on case series on literature reviews,comparative studies and cost-utility analysis which have been selected based on criteria regarding surgery,possible prognostic factors and evaluation of long-term ***:There is a strong inhomogeneity in the reported data,with 5-year survivals ranging from 21%to 58%.There is no agreement in the evaluation of prognostic variables predicting good survival,with the only exception of the time of treatment of the primary BC until the diagnosis of *** out of the four comparative studies report better survivals for patients who underwent a hepatectomy in comparison to those treated with chemotherapy alone,but their strength in terms of scientific evidence is *** only cost-utility analysis revealed that 2 out of the 3 scenarios considered were in favor of the treatment with surgery followed by conventional ***:There is no definitive proof on the effectiveness of LRs for BC *** can be proposed when it is possible to perform radical surgery,with R0 margins and saving at least 30%of the liver with its vascular and biliary *** skeletal metastases are not a *** interval between treatment of the primary location and diagnosis of hepatic metastases is the only prognosis criteria available.

关键词： Breast cancer(BC) liver metastases(LM) liver surgery hepatectomy

Spectral and fragility evaluations of retrofitted structures through strength reduction and enhanced damping

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Earthquake Engineering and Engineering Vibration 2009年第1期8卷 115-125页

作者： gian Paolo Cimellaro Hwasung Roh Alessandro De Stefano Department of Structural & Geotechnical Engineering (DISTR) Polytechnic of Turin Turin Italy Department of Civil Structural & Environmental Engineering University at Buffalo The State University of New York Buffalo USA

A retrofit procedure for existing buildings called the ＂weakening and damping technique＂（WED） is presented in this paper. Weakening of structures can limit the maximum response accelerations during severe ground motions, but leads to an increase in the displacements or inter-story drifts. Added damping by using viscous dampers, on the other hand, reduces the inter-story drifts and has no significant effect on total accelerations, when structures behave inelastically. The weakening and damping technique addresses the two main causes for both structural and nonstructural damage in structures. The weakening retrofit is particularly suitable for structures that have overstressed components and weak brittle components. In this paper, the advantages of the WeD are verified by nonlinear dynamic analysis and simplified spectral approach that has been modified to fit structures with additional damping devices. A hospital structure located in the San Fernando Valley in California is selected as a case study. The results from both analyses show that the retrofit solution is feasible to reduce both structural acceleration and displacement. A sensitivity analysis is also carried out to evaluate the effectiveness of the retrofitting method using different combinations of performance thresholds in accelerations and displacements through fragility analysis.

关键词： weakening damping retrofit inelastic spectral response fragility analysis nonlinear dynamic analysis

Photorealistic modelling of metals from first principles

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npj Computational Materials 2019年第1期5卷 1-12页

作者： gianluca Prandini gian-Marco Rignanese Nicola Marzari Theory and Simulation of Materials(THEOS)and National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de Lausanne1015 LausanneSwitzerland Institute of Condensed Matter and Nanosciences(IMCN) Universitécatholique de Louivain1348 Louvain-la-NeuveBelgium

The colours of metals have attracted the attention of humanity since ancient times,and coloured metals,in particular gold compounds,have been employed for tools and objects symbolizing the aesthetics of *** this work,we develop a comprehensive framework to obtain the reflectivity and colour of metals,and show that the trends in optical properties and the colours can be predicted by straightforward first-principles techniques based on standard *** apply this to predict reflectivity and colour of several elemental metals and of different types of metallic compounds(intermetallics,solid solutions and heterogeneous alloys),considering mainly binary alloys based on noble *** validate the numerical approach through an extensive comparison with experimental data and the photorealistic rendering of known coloured metals.

关键词： alloys intermetallics metals

Materials property prediction for limited datasets enabled by feature selection and joint learning with MODNet

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npj Computational Materials 2021年第1期7卷 731-738页

作者： Pierre-Paul De Breuck Geoffroy Hautier gian-Marco Rignanese UCLouvain Institute of Condensed Matter and Nanosciences(IMCN)Louvain-la-NeuveBelgium Dartmouth College Thayer School of EngineeringHanoverNHUSA

In order to make accurate predictions of material properties,current machine-learning approaches generally require large amounts of data,which are often not available in *** this work,MODNet,an all-round framework,is presented which relies on a feedforward neural network,the selection of physically meaningful features,and when applicable,*** to being faster in terms of training time,this approach is shown to outperform current graph-network models on small *** particular,the vibrational entropy at 305 K of crystals is predicted with a mean absolute test error of 0.009 meV/K/atom(four times lower than previous studies).Furthermore,joint learning reduces the test error compared to single-target learning and enables the prediction of multiple properties at once,such as temperature ***,the selection algorithm highlights the most important features and thus helps to understand the underlying physics.

关键词： learning prediction property

Discovery of an unknown conduction mechanism in insulating polymers

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High Voltage 2020年第4期5卷 403-408页

作者： gian Carlo Montanari Paolo Seri Leonard A.Dissado Center for Advanced Power Systems Florida State University2000 Levy AvenueFL 32310USA DEI University of BolognaViale del Risorgimento2–40136BolognaItaly Department of Engineering University of LeicesterUniversity RoadLeicesterLE17RHUK

Polymer dielectrics are widely used in electrical and electronic apparatus and devices because of their capability to insulate conductors,withstand high fields and suffer negligible conductive *** near-to-zero conductivity has been explained in terms of long-accepted theories of electronic and ionic transport that lead to the accumulation of local net charge regions at high electric *** the authors describe a previously unknown conduction mechanism consisting of small bipolar ultra-fast charge pulses crossing the polymer with the mobility,as large as,4 to 5 orders of magnitude greater than that of the previously *** authors show that this motion is a consequence of molecular relaxation processes triggered by the electric field locally enhanced by the pulses *** accumulation at the electrodes increases interface field and thus contributes substantially towards premature failure in insulating dielectrics in DC fields.

关键词： conduction mechanism negligible

AFM Measurements and Tip Characterization of Nanoparticles with Different Shapes

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Nanomanufacturing and Metrology 2022年第2期5卷 127-138页

作者： Roberto Bellotti gian Bartolo Picotto Luigi Ribotta Istituto Nazionale di Ricerca Metrologica(INRiM) Strada delle Cacce 9110135TorinoItaly Politecnico di Torino Corso Duca degli Abruzzi 2410129TorinoItaly

Unambiguous identification of the measurement methodologies is fundamental to reduce the uncertainty and support traceability of particle shape and size at the nanoscale. In this work, the critical aspects in atomic force microscopy measurements, that is, drawbacks on sample preparation, instrumental parameters, image pre-processing, size reconstruction, and tip enlargement, are discussed in reference to quantitative dimensional measurements on different kinds of nanoparticles (inorganic and biological) with different shapes (spherical, cylindrical, complex geometry). Once the cross-section profile is extracted, top-height measurements on isolated nanoparticles of any shape can be achieved with sub-nanometer accuracy. Lateral resolution is affected by the pixel size and shape of the probe, causing dilation in the atomic force microscopy image. For the reconstruction of critical sizes of inorganic non-spherical nanoparticles, a geometric approach that considers the nominal shape because of the synthesis conditions is presented and discussed.

关键词： Nanoparticles(NPs) Atomic force microscopy(AFM) Size reconstruction Spherical shape Complex shape AFM probe Uncertainty