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Reasons of PEG failure to eliminate gastroesophageal reflux in mechanically ventilated patients

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World Journal of Gastroenterology 2009年第43期15卷 5455-5460页

作者： Emmanuel E Douzinas Ilias Andrianakis Olga Livaditi Dimitrios Bakos katerina Flevari Nikos Goutas Dimitrios Vlachodimitropoulos marios-konstantinos tasoulis Alex P Betrosian 3rd Department of Critical Care Evgenidion HospitalUniversity of Athens Medical School Athens 115 28Greece The Laboratory of Pathology Evgenidion HospitalUniversity of Athens Medical SchoolAthens 115 28Greece

AIM： To investigate factors predicting failure of percutaneous endoscopic gastrostomy （PEG） to eliminate gastroesophageal reflux （GER）. METHODS： Twenty-nine consecutive mechanically ventilated patients were investigated. Patients were evaluated for GER by pH-metry pre-PEG and on the 7th post-PEG day. Endoscopic and histologic evidence of reflux esophagitis was also carried out. A beneficial response to PEG was considered when pH-metry on the 7th post-PEG day showed that GER was below 4%. RESULTS： Seventeen patients responded （RESP group） and 12 did not respond （N-RESP） to PEG. The mean age, sex, weight and APACHE II score were similar in both groups. GER （%） values were similar in both groups at baseline, but were significantly reduced in the RESP group compared with the N-RESP group on the 7th post-PEG day [2.5 （0.6-3.8） vs 8.1 （7.4-9.2, P 〈 0.001）]. Reflux esophagitis and the gastroesophageal flap valve （GEFV） grading differed significantly between the two groups （P = 0.031 and P = 0.020, respectively）. Histology revealed no significant differences between the two ***： Endoscopic grading of GEFV and the presence of severe reflux esophagitis are predisposing factors for failure of PEG to reduce GER in mechanically ventilated patients.

关键词： Esophagitis Gastroesophageal reflux Percutaneous endoscopic gastrostomy

Fault Accommodation for a Class of Nonlinear Uncertain Systems With Event-Triggered Input

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IEEE/CAA Journal of Automatica Sinica 2022年第2期9卷 235-245页

作者： Dong Zhao marios M.Polycarpou IEEE kIOS Research and Innovation Center of Excellence and the Department of Electrical and Computer EngineeringUniversity of CyprusNicosia 1678Cyprus

The event-triggered fault accommodation problem for a class of nonlinear uncertain systems is considered in this *** control signal transmission from the controller to the system is determined by an event-triggering scheme with relative and constant triggering *** the event-induced control input error and system fault threat,a novel eventtriggered active fault accommodation scheme is designed,which consists of an event-triggered nominal controller for the time period before detecting the occurrence of faults and an adaptive approximation based event-triggered fault accommodation scheme for handling the unknown faults after detecting the occurrence of *** closed-loop stability and inter-event time of the proposed fault accommodation scheme are rigorously *** cases for the fault accommodation design under constant triggering threshold are also *** example is employed to illustrate the effectiveness of the proposed fault accommodation scheme.

关键词： Adaptive control event-triggered control fault accommodation neural networks nonlinear systems

A numerical study of prestressed high strength steel tubular members

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Frontiers of Structural and Civil Engineering 2020年第1期14卷 10-22页

作者： Michaela GkANTOU marios THEOFANOUS Charalampos BANIOTOPOULOS Department of Civil Engineering Liverpool John Moores UniversityLiverpool L33AFUK Department of Civil Engineering University of BirminghamBirmingham B152TTUK

The structural behavior of prestressed high strength steel(HSS)tubular members is investigated through the execution of advanced finite element *** models are developed and validated against published experimental data on HSS tubular members subjected to different levels of initial prestress and loaded either in tension or *** effect of the presence or absence of grouting on the strength and ductility of the members is also *** numerically replicate the structural response recorded in the tests,some key modeling features including the employed numerical solver,the adopted material models and the element types warrant careful *** developing of the finite element models,the numerically generated ultimate loads,the corresponding failure modes and the full load-deformation curves are compared to the experimental ones,indicating a successful *** anticipated,prestressing enhances the load-bearing capacity for the tensile members,whereas it is detrimental for the compressive ones.A series of parametric studies is performed to assess the influence of key factors on the structural response of prestressed HSS members and the obtained results are *** guidance for tensile and compressive prestressed tubular members is also provided.

关键词： finite element prestressing tubular members grout high strength steel

Post-glass melting synthesis and photochromic properties of composite AgCl-AgPO_(3)glasses

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Journal of Materiomics 2023年第3期9卷 455-463页

作者： marios Adamidis Ioannis konidakis Emmanuel Stratakis Institute of Electronic Structure and Laser(IESL) Foundation for Research and Technology-Hellas(FORTH)HeraklionCrete71110Greece Department of Materials Science and Technology University of CreteHeraklionCrete71003Greece

We herein present a simple,fast,low-temperature,post-glass melting fabrication protocol in which a photochromic silver cation based modified zone is incorporated within silver metaphosphate glass(AgPO_(3)).The selection of AgPO_(3)glass is mainly based on its relative“soft”nature(T_(g)=192℃)that enables the integration of silver cations from the surface deposited AgCl layer,while being transparent in most of the visible range,and therefore suitable for smart photochromic window *** suggested synthesis procedure permits the controlled formation of a silver cation modified layer within the host glass matrix,while the characteristics of the layer itself can be adjusted *** findings reveal a direct relationship between the developed composite AgCleAgPO_(3)glass photochromic response and the morphological features of the integrated layer,i.e.,thickness and *** importantly,the photochromic response time with various UV irradiation doses is also studied,where remarkable response times of several seconds are *** and efforts to further enhance the photochromic performance by utilizing the presence of silver nanoparticles within the glass matrix are also presented and discussed.

关键词： Silver chloride Silver metaphosphate glass Soft phosphate glass Post-glass melting incorporation Photochromic properties

Two-way coupling of unsaturated-saturated flow by integrating the SWAT and MODFLOW models with application in an irrigation district in arid region of West China

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Journal of Arid Land 2011年第3期3卷 164-173页

作者： Yi LUO marios SOPHOCLEOUS Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China kansas Geological Survey University of Kansas Lawrence Kansas 66047 USA

This paper presents the realization of two-way coupling of the unsaturated-saturated flow interactions of the SWAT2000 and MODFLOW96 models on the basis of the integrated surface/groundwater model SWATMOD99, and its application in Hetao Irrigation District （HID）, Inner Mongolia, China. Major revisions and enhancements were made to the SWAT2000 and MODFLOW models for simulating the detailed hydrologic budget and coupled unsaturated and saturated interactions, and irrigation canal hydrology for the HID. The simulation results of seasonal groundwater recharge to and evaporate from the shallow groundwater, and the annual water budget over the district are presented and discussed. The results implied the necessity of two-way coupling of the unsaturated-saturated interactions when groundwater is shallow, and the feasibility of making comprehensive use of the information coming from both the surface water and groundwater models to make a more physically-based assessment of the coupled interactions.

关键词： SWAT MODFLOW SWATMOD coupled unsaturated-saturated flow irrigation canals groundwater recharge groundwater evaporation

Anharmonic electron-phonon coupling in ultrasoft and locally disordered perovskites

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npj Computational Materials 2023年第1期9卷 744-756页

作者： marios Zacharias George Volonakis Feliciano Giustino Jacky Even Univ Rennes INSA RennesCNRSInstitut FOTON-UMR 6082F-35000 RennesFrance Univ Rennes ENSCRINSA RennesCNRSISCR-UMR 6226F-35000 RennesFrance Oden Institute for Computational Engineering and Sciences The University of Texas at AustinAustinTX 78712USA Department of Physics The University of Texas at AustinAustinTX 78712USA

Anharmonicity and local disorder(polymorphism)are ubiquitous in perovskite physics,inducing various phenomena observed in scattering and spectroscopy *** of these phenomena still lack interpretation from first principles since,hitherto,no approach is available to account for anharmonicity and disorder in electron–phonon ***,relying on the special displacement method,we develop a unified treatment of both and demonstrate that electron–phonon coupling is strongly influenced when we employ polymorphous perovskite *** uncover that polymorphism in halide perovskites leads to vibrational dynamics far from the ideal noninteracting phonon picture and drives the gradual change in their band gap around phase transition *** also clarify that combined band gap corrections arising from disorder,spin-orbit coupling,exchange–correlation functionals of high accuracy,and electron–phonon coupling are all *** findings agree with experiments,suggesting that polymorphism is the key to address pending questions on perovskites’technological applications.

关键词： perovskite phonon harmonic

Finite-Time Distributed Identification for Nonlinear Interconnected Systems

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IEEE/CAA Journal of Automatica Sinica 2022年第7期9卷 1188-1199页

作者： Farzaneh Tatari Hamidreza Modares Christos Panayiotou marios Polycarpou Mechanical Engineering Department Michigan State UniversityEast LansingMI 48824 USA kIOS Research and Innovation Center of Excellence and the Department of Electrical and Computer Engineering University of CyprusNicosia 1678Cyprus IEEE

In this paper,a novel finite-time distributed identification method is introduced for nonlinear interconnected systems.A distributed concurrent learning-based discontinuous gradient descent update law is presented to learn uncertain interconnected subsystems’*** concurrent learning approach continually minimizes the identification error for a batch of previously recorded data collected from each subsystem as well as its neighboring *** state information of neighboring interconnected subsystems is acquired through direct *** overall update laws for all subsystems form coupled continuous-time gradient flow dynamics for which finite-time Lyapunov stability analysis is *** a byproduct of this Lyapunov analysis,easy-to-check rank conditions on data stored in the distributed memories of subsystems are obtained,under which finite-time stability of the distributed identifier is *** rank conditions replace the restrictive persistence of excitation(PE)conditions which are hard and even impossible to achieve and verify for interconnected ***,simulation results verify the effectiveness of the presented distributed method in comparison with the other methods.

关键词： Distributed concurrent learning finite-time identification nonlinear interconnected systems unknown dynamics

Neural network analysis of overturning response under near-fault type excitation

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Earthquake Engineering and Engineering Vibration 2005年第2期4卷 213-228页

作者： Nikos Gerolymos marios Apostolou George Gazetas School of Civil Engineering National Technical UniversityAthensGreece Post-doctoralResearch Engineer School of Civil Engineering National Technical UniversityAthensGreece Ph.D.Student School of Civil Engineering National Technical UniversityAthensGreece Professor

Under strong seismic excitation, a rigid block will uplift from its support and undergo rocking oscillations which may lead to （complete） overturning. Numerical and analytical solutions to this highly nonlinear vibration problem are first highlighted in the paper and then utilized to demonstrate how sensitive the overturning behavior is not only to the intensity and frequency content of the base motion, but also to thc presence of strong pulses, to their detailed sequence, and even to their asymnletry. Five idealised pulses capable of representing ＂rupture-directivity＂ and ＂fling＂ affected ground motions near the fault, are utilized to this end ： the one-cycle sinus, the one-cycle cosinus, the Ricker wavelet, the truncated （T）-Ricker wavelet, and the rectangular pulse ＂Overturning-Acceleration Amplification＂ and ＂Rotation＂ spectra are introduced and presented. Artificial neural network modeling is then developed as an alternative numerical solution. The neural network analysis leads to closed-form expressions for predicting the overturning failure or survival of a rigid block, as a function of its geometric properties and the characteristics of the excitation time history. The capability of the developed neural network modeling is validated through comparisons with the numerical solution. The derived analytical expressions could also serve as a tool for assessing the destructiveness of near-fault ground motions, for structures sensitive to rocking with foundation uplift.

关键词： overturning uplifting pulse near-fault moti neural network rocking spectrum kocaeli records

A comparison between friction stir welding, linear friction welding and rotary friction welding

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Advances in Manufacturing 2016年第4期4卷 296-304页

作者： Achilles Vairis George Papazafeiropoulos Andreas-marios Tsainis Department of Mechanical Engineering TechnologicalEducation Institute of Crete Heraklion Crete Greece Institute of Structural Analysis and Antiseismic Research National Technical University of Athens Zografou CampusAthens 15780 Greece Faculty of Science Engineering and Computing KingstonUniversity London UK

Three friction welding processes are compared for temperature, stresses and strains, as well as strain rates developed in the early phases of the processes, which are essential in their successful development. These are friction stir welding （FSW）, linear friction welding （LFW） and rotary friction welding （RFW）. Their common characteristic is the use of friction to generate adequate energy and raise temperature locally in order to create favorable conditions for welding at the interface between two parts. Although the mode of movement is different for each one of them, welds are produced through plastic deformation. The Lagrangian and coupled Eulerian-Lagrangian numer- ical models developed have produced results which are in qualitative agreement with experiments and have shed a light on the commonalities of these friction welding processes

关键词： Friction welding (FW) Finite elementanalysis Thermo-mechanical process Ti-6A1-4V