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International Journal of Sediment Research 2014年第3期29卷 304-315页

作者： Achilleas g.SAMARAS christopher g.koutitas Research Fellow CIRI-ECFluid Dynamics Research UnitUniversity of BolognaVia del Lazzaretto 15/5Bologna 40131Italy Department of Civil Engineering Aristotle University of ThessalonikiUniversity Campus

Climate change is an issue of major concern *** impact on the natural and human environment is studied intensively,as the expected shift in climate will be significant in the next few *** experience shows that the effects will be critical in coastal areas,resulting in erosion and inundation phenomena *** addition to that,coastal areas are subject to "pressures" from upstream watersheds in terms of water quality and sediment *** present paper studies the impact of climate change on sediment transport and morphology in the aforementioned coupled *** study regards a sandy coast and its upstream watershed in Chalkidiki,North greece;it is based on:(a)an integrated approach for the quantitative correlation of the two through numerical modeling,developed by the authors,and(b)a calibrated application of the relevant models Soil and Water Assessment Tool(SWAT)and PELNCON-M,applied to the watershed and the coastal zone,*** examined climate change scenarios focus on a shift of the rainfall distribution towards fewer and more extreme rainfall events,and an increased frequency of occurrence of extreme wave *** indicate the significance of climatic pressures in wide-scale sediment dynamics,and are deemed to provide a useful perspective for researchers and policy planners involved in the study of coastal morphology evolution in a changing climate.

关键词： Climate change Sediment transport Coastal morphology Integrated approach Numerical modeling

Apples to oranges:environmentally derived,dynamic regulation of serotonin neuron subpopulations in adulthood?

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Neural Regeneration Research 2025年第9期20卷 2596-2597页

作者： christopher J.O’Connell Matthew J.Robson Department of genetics College of MedicineHarvard UniversityBostonMAUSA James L.Winkle College of Pharmacy Division of Pharmaceutical SciencesUniversity of CincinnatiCincinnatiOHUSA Neuroscience graduate Program College of MedicineUniversity of CincinnatiCincinnatiOHUSA

Traumatic brain injury(TBI)is a public health problem with an undue economic burden that impacts nearly every age,ethnic,and gender group across the globe(Capizzi et al.,2020).TBIs are often sustained during a dynamic range of exposures to energetic environmental forces and as such outcomes are typically heterogeneous regarding severity and pathology(Capizzi et al.,2020).

关键词： sustained orange dynamic

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Incremental Static Analysis of 2D Flow by Inter-Colliding Point-Particles and Use of Incompressible Rhombic Element

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Open Journal of Civil Engineering 2016年第3期6卷 397-409页

作者： Panagis g. Papadopoulos christopher g. koutitas Panos P. Lazaridis Department of Civil Engineering Aristotle University of Thessaloniki Thessaloniki Greece

A simple method is proposed, for incremental static analysis of a set of inter-colliding particles, simulating 2D flow. Within each step of proposed algorithm, the particles perform small displacements, proportional to the out-of-balance forces, acting on them. Numerical experiments show that if the liquid is confined within boundaries of a set of inter-communicating vessels, then the proposed method converges to a final equilibrium state. This incremental static analysis approximates dynamic behavior with strong damping and can provide information, as a first approximation to 2D movement of a liquid. In the initial arrangement of particles, a rhombic element is proposed, which assures satisfactory incompressibility of the fluid. Based on the proposed algorithm, a simple and short computer program (a “pocket” program) has been developed, with only about 120 Fortran instructions. This program is first applied to an amount of liquid, contained in a single vessel. A coarse and refined discretization is tried. In final equilibrium state of liquid, the distribution on hydro-static pressure on vessel boundaries, obtained by proposed computational model, is found in satisfactory approximation with corresponding theoretical data. Then, an opening is formed, at the bottom of a vertical boundary of initial vessel, and the liquid is allowed to flow gradually to an adjacent vessel. Almost whole amount of liquid is transferred, from first to second vessel, except of few drops-particles, which remain, in equilibrium, at the bottom of initial vessel. In the final equilibrium state of liquid, in the second vessel, the free surface level of the liquid confirms that the proposed rhombing element assures a satisfactory incompressibility of the fluid.

关键词： 2D Flow Simulation Inter-Colliding Point-Particles Incremental Static Analysis Incompressible Rhombic Element Hydro-Static Pressure Distribution Flow from a Vessel to Another One “Pocket” Special Purpose Computer Program

Comparative analysis of empirical and deep learning models for ionospheric sporadic E layer prediction

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Earth and Planetary Physics 2025年第1期9卷 10-19页

作者： BingKun Yu PengHao Tian XiangHui Xue christopher JScott HaiLun Ye JianFei Wu Wen Yi TingDi Chen XianKang Dou Institute of Deep Space Sciences Deep Space Exploration LaboratoryHefei 230088China CAS Key Laboratory of geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China Department of Meteorology University of ReadingReading RG66BBUK

Sporadic E(Es)layers in the ionosphere are characterized by intense plasma irregularities in the E region at altitudes of 90-130 *** they can significantly influence radio communications and navigation systems,accurate forecasting of Es layers is crucial for ensuring the precision and dependability of navigation satellite *** this study,we present Es predictions made by an empirical model and by a deep learning model,and analyze their differences comprehensively by comparing the model predictions to satellite RO measurements and ground-based ionosonde *** deep learning model exhibited significantly better performance,as indicated by its high coefficient of correlation(r=0.87)with RO observations and predictions,than did the empirical model(r=0.53).This study highlights the importance of integrating artificial intelligence technology into ionosphere modelling generally,and into predicting Es layer occurrences and characteristics,in particular.

关键词： ionospheric sporadic E layer radio occultation ionosondes numerical model deep learning model artificial intelligence

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Retzius-sparing robotic radical prostatectomy

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Asian Journal of Andrology 2020年第2期22卷 149-151页

作者： christopher g Eden Department of Urology The Royal Surrey County HospitalGuildford GU27XXUK

Traditional approach to the prostate during radical prostatectomy(RP)when performed by open,laparoscopic,or robotic means has been from its anterior aspect first and has involved suture ligation and division of the dorsal vein complex(DVC),division of the puboprostatic ligaments,and incision of the endopelvic fascia on either side of the *** steps are necessary to liberate the prostate from its surrounding attachments,even though concern has always existed about the likely association between disruption of these structures and postprostatectomy incontinence(PPI).Although perineal prostatectomy leaves these structures intact,it has failed to become widely accepted because of the small incidence of postoperative fecal incontinence and the difficulty in performing a pelvic lymphadenectomy(PLND)when this is indicated.

关键词： robotic radical steps

mTORC1 signaling:what we still don’t know

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Journal of Molecular Cell Biology 2011年第4期3卷 206-220页

作者： Xuemin Wang christopher g.Proud School of Biological Sciences Life Sciences BuildingUniversity of SouthamptonSouthampton SO171BJUK

The mammalian target of rapamycin(mTOR)is a protein kinase that plays key roles in cellular *** forms complexes with additional *** best-understood one is mTOR complex 1(mTORC1).The regulation and cellular functions of mTORC1 have been the subjects of intense study;despite this,many questions remain to be *** include questions about the actual mechanisms by which mTORC1 signaling is stimulated by hormones and growth factors,which involves the small gTPase Rheb,and by amino acids,which involves other gTPase *** control of Rheb and the mechanism by which it activates mTORC1 remain incompletely *** it has been known for many years that rapamycin interferes with some functions of mTORC1,it is not known how it does this,or why only some functions of mTORC1 are ***1 regulates diverse cellular *** mTORC1 substrates are now known,although in several cases their physiological roles are poorly or incompletely *** the case of several processes,although it is clear that they are regulated by mTORC1,it is not known how mTORC1 does ***,mTORC1 is implicated in ageing,but again it is unclear what mechanisms account for *** the importance of mTORC1 signaling both for cellular functions and in human disease,it is a high priority to gain further insights into the control of mTORC1 signaling and the mechanisms by which it controls cellular functions and animal physiology.

关键词： mTORC1 protein synthesis cell signaling transcription cell growth autophagy metabolism

Simplified Coarse-grained Dynamic Model for Real gases

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Open Journal of Physical Chemistry 2017年第2期7卷 50-71页

作者： Panagis g. Papadopoulos christopher g. koutitas Yannis N. Dimitropoulos Elias C. Aifantis Department of Civil Engineering Aristotle University of Thessaloniki Thessaloniki Greece Department of Chemistry University of Ioannina Ioannina Greece

A simplified model is proposed for an easy understanding of the coarse-grained technique and for achieving a first approximation to the behavior of gases. A mole of a gas substance, within a cubic container, is represented by six particles symmetrically moving. The impacts of particles on container walls, the inter-particle collisions, as well as the volume of particles and the inter-particle attractive forces, obeying a Lennard-Jones curve, are taken into account. Thanks to the symmetry, the problem is reduced to the nonlinear dynamic analysis of a SDOF oscillator, which is numerically solved by a step-by-step time integration algorithm. Five applications of proposed model, on Carbon Dioxide, are presented: 1) Ideal gas in STP conditions. 2) Real gas in STP conditions. 3) Condensation for small molar volume. 4) Critical point. 5) Iso-kinetic energy curves and iso-therms in the critical point region. Results of the proposed model are compared with test data and results of the Van der Waals model for real gases.

关键词： Real gases Coarse-grained Molecular Dynamics Particles Volume Inter-Particle Attractive Forces Lennard-Jones Curve Step-by-Step Time Integration Algorithm Condensation Critical Point Iso-Kinetic Energy Curves Iso-Therms Van der Waals Model

Simplified Step-by-Step Nonlinear Static Program Investigating Equilibrium Conditions of Electrons in Atom and Ionization Energies: Case Study on Argon

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Open Journal of Physical Chemistry 2018年第2期8卷 33-56页

作者： Panagis g. Papadopoulos christopher g. koutitas Yannis N. Dimitropoulos Elias C. Aifantis Structural Engineering Division Civil Engineering Department Aristotle University of Thessaloniki Thessaloniki Greece Fluid Mechanics Division Civil Engineering Department Aristotle University of Thessaloniki Thessaloniki Greece Physical Chemistry Division Chemistry Department University of Ioannina Ioannina Greece Aristotle University of Thessaloniki Thessaloniki Greece Michigan Technological University Houghton MI USA Beijing University of Civil Engineering and Architecture Beijing China ITMO University St. Petersburg Russia Togliatti State University Togliatti Russia

For investigation of equilibrium conditions of electrons in an atom, and Ionization Energies of Elements, a simplified deterministic static model is proposed. The electrons are initially uniformly and sparsely arranged on the outer surface of nucleus. Then, by taking into account the nucleus-electron interaction (attractive and repulsive) and the mutual electron-electron repulsions, and by a simple step-by-step nonlinear static analysis program, all the electrons are found to equilibrate on the outer surface of the same sphere, which is concentric and larger than nucleus. In a second stage, starting from an equilibrium sphere of electrons, one of the electrons is subjected to gradual forced removal, radially and outwards with respect to nucleus. Within each removal step, the produced work increment is determined and the increments are summed. When no more significant attraction is exerted by nucleus to removed electron, the total work gives the Ionization Energy. After removing of single electron, the remaining electrons fall on a lower shell, that is, they equilibrate on the outer surface of a smaller concentric sphere. For nucleus-electron interaction, an L-J (Lennard-Jones) type curve, attractive and repulsive, is adopted. When the parameter of this curve is n > 1.0, the Ionization Energy exhibits an upper bound. As parameter n increases from 1.0 up to 2.0, the attractive potential of L-J curve is gradually weakened. The proposed model is applied on Argon. It is observed that, as the number of electrons increases, the radius of equilibrium sphere increases, too, whereas the attractive nucleus-electron potential is reduced;thus the Ionization Energy is reduced, too. Particularly, as the number of electrons and the radius of equilibrium sphere exceed some critical values, the above two last quantities exhibit abrupt falls. A regular polyhedron is revealed, which can accommodate Elements up to atomic number Z = 146, that is 28 more than Z = 118 of existing last Elem

关键词： Ionization Energy Electrostatic Laws Lennard-Jones Curve Incremental Nonlinear Static Analysis Atomic Radius Rhombic Dodecahedron Regular Polyhedron

Neighboring optimal control for periodic tasks for systems with discontinuous dynamics

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Science China(Information Sciences) 2011年第3期54卷 653-663页

作者： ATKESON christopher g. Robotics Institute Carnegie Mellon University

We propose a trajectory-based optimal control method for periodic tasks for systems with discontinuous dynamics. A general method, dynamic programming, suffers from the problem of dimensionality. We use local models of the optimal control law to construct a local controller. We combine a parametric trajectory optimization method and differential dynamic programming (DDP) to find the optimal periodic trajectory in a periodic task. By formulating the optimal control problem with an infinite time horizon, DDP generates time-invariant local models of the optimal control law. For DDP, the value function at dynamics discontinuities is approximated by a second order Taylor series. The utility of the proposed method is evaluated using simu- lated walking control of a five-link biped robot. The results show lower torques and more robustness from the proposed controller than a PD servo controller.

关键词： trajectory optimization differential dynamic programming optimal control biped walking control

Simple Rational Model for Discharge of Batteries with Aqueous Electrolytes, Based on Nernst Equation

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Open Journal of Physical Chemistry 2021年第1期11卷 1-11页

作者： Panagis g. Papadopoulos christopher g. koutitas Christos g. Karayannis Panos D. Kiousis Yannis N. Dimitropoulos Department of Civil Engineering Aristotle University of Thessaloniki Thessaloniki Greece Department of Civil Engineering Democritus University of Thrace Xanthi Greece Department of Structural and geotechnical Engineering Colorado School of Mines Golden CO USA Department of Chemistry University of Ioannina Ioannina Greece

A simple rational model is proposed for discharge of batteries with aqueous electrolytes, based on Nernst equation. Details of electrode kinetics are not taken into account. Only a few overall parameters of the battery are considered. A simple algorithm, with variable time step-length Δt, is presented, for proposed model. The model is first applied to Daniel cell, in order to clarify concepts and principles of battery operation. It is found that initial pinching, in time-history curve of voltage E-t, is due to initial under-concentration of product ion. Then, model is applied to a lead-acid battery. In absence of an ion product, and in order to construct nominator of Nernst ratio, such an ion, with coefficient tending to zero, is assumed, thus yielding unity in nominator. Time-history curves of voltage, for various values of internal resistance, are compared with corresponding published experimental curves. Temperature effect on voltage-time curve is examined. Proposed model can be extended to other types of batteries, which can be considered as having aqueous electrolytes, too.

关键词： Battery Aqueous Electrolyte Discharge Nernst Equation Daniel Cell Lead-Acid Battery Temperature Effect