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Gotowa bibliografia na temat „Proton kinetic energy”

Autor: Grafiati

Data publikacji: 6 września 2023

Data aktualizacji: 7 września 2023

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Artykuły w czasopismach na temat "Proton kinetic energy"

Liang, Ruibin, Jessica M. J. Swanson, Mårten Wikström i Gregory A. Voth. "Understanding the essential proton-pumping kinetic gates and decoupling mutations in cytochrome c oxidase". Proceedings of the National Academy of Sciences 114, nr 23 (23.05.2017): 5924–29. http://dx.doi.org/10.1073/pnas.1703654114.

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Cytochrome c oxidase (CcO) catalyzes the reduction of oxygen to water and uses the released free energy to pump protons against the transmembrane proton gradient. To better understand the proton-pumping mechanism of the wild-type (WT) CcO, much attention has been given to the mutation of amino acid residues along the proton translocating D-channel that impair, and sometimes decouple, proton pumping from the chemical catalysis. Although their influence has been clearly demonstrated experimentally, the underlying molecular mechanisms of these mutants remain unknown. In this work, we report multiscale reactive molecular dynamics simulations that characterize the free-energy profiles of explicit proton transport through several important D-channel mutants. Our results elucidate the mechanisms by which proton pumping is impaired, thus revealing key kinetic gating features in CcO. In the N139T and N139C mutants, proton back leakage through the D-channel is kinetically favored over proton pumping due to the loss of a kinetic gate in the N139 region. In the N139L mutant, the bulky L139 side chain inhibits timely reprotonation of E286 through the D-channel, which impairs both proton pumping and the chemical reaction. In the S200V/S201V double mutant, the proton affinity of E286 is increased, which slows down both proton pumping and the chemical catalysis. This work thus not only provides insight into the decoupling mechanisms of CcO mutants, but also explains how kinetic gating in the D-channel is imperative to achieving high proton-pumping efficiency in the WT CcO.

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Shematovich, V. I. "Atmospheric Loss of Atomic Oxygen during Proton Aurorae on Mars". Solar System Research 55, nr 4 (lipiec 2021): 324–34. http://dx.doi.org/10.1134/s0038094621040079.

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Abstract— For the first time, the calculations of the penetration of protons of the undisturbed solar wind into the daytime atmosphere of Mars due to charge exchange in the extended hydrogen corona (Shematovich et al., 2021) are used allowing us to determine self-consistently the sources of suprathermal oxygen atoms, as well as their kinetics and transport. An additional source of hot oxygen atoms—collisions accompanied by the momentum and energy transfer from the flux of precipitating high-energy hydrogen atoms to atomic oxygen in the upper atmosphere of Mars—was included in the Boltzmann kinetic equation, which was solved with the Monte-Carlo kinetic model. As a result, the population of the hot oxygen corona of Mars has been estimated; and it has been shown that the proton aurorae are accompanied by the atmospheric loss of atomic oxygen, which is evaluated within a range of (3.5–5.8) × 107 cm–2 s–1. It has been shown that the exosphere becomes populated with a substantial amount of suprathermal oxygen atoms with kinetic energies up to the escape energy, 2 eV. The atomic oxygen loss rate caused by a sporadic source in the Martian atmosphere—the precipitation of energetic neutral atoms of hydrogen (H‑ENAs) during proton aurorae at Mars—was estimated by the self-consistent calculations according to a set of the Monte-Carlo kinetic models. These values turned out be comparable to the atomic oxygen loss supported by a regular source—the exothermic photochemical reactions (Groeller et al., 2014; Jakosky et al., 2018). It is currently supposed that the atmospheric loss of Mars due to the impact of the solar wind plasma and, in particular, the fluxes of precipitating high-energy protons and hydrogen atoms during solar flares and coronal mass ejections may play an important role in the loss of the neutral atmosphere on astronomic time scales (Jakosky et al., 2018).

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Jones, S. B., T. S. Nonnenmacher, E. Atkin, G. J. Barker, A. Basharina-Freshville, C. Betancourt, S. B. Boyd i in. "Off-Axis Characterisation of the CERN T10 Beam for low Momentum Proton Measurements with a High Pressure Gas Time Projection Chamber". Instruments 4, nr 3 (28.07.2020): 21. http://dx.doi.org/10.3390/instruments4030021.

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We present studies of proton fluxes in the T10 beamline at CERN. A prototype high pressure gas time projection chamber (TPC) was exposed to the beam of protons and other particles, using the 0.8 GeV/c momentum setting in T10, in order to make cross section measurements of low energy protons in argon. To explore the energy region comparable to hadrons produced by GeV-scale neutrino interactions at oscillation experiments, i.e., near 0.1 GeV of kinetic energy, methods of moderating the T10 beam were employed: the dual technique of moderating the beam with acrylic blocks and measuring scattered protons off the beam axis was used to decrease the kinetic energy of incident protons, as well as change the proton/minimum ionising particle (MIP) composition of the incident flux. Measurements of the beam properties were made using time of flight systems upstream and downstream of the TPC. The kinetic energy of protons reaching the TPC was successfully changed from ∼0.3 GeV without moderator blocks to less than 0.1 GeV with four moderator blocks (40 cm path length). The flux of both protons and MIPs off the beam axis was increased. The ratio of protons to MIPs vary as a function of the off-axis angle allowing for possible optimisation of the detector to select the type of required particles. Simulation informed by the time of flight measurements show that with four moderator blocks placed in the beamline, (5.6 ± 0.1) protons with energies below 0.1 GeV per spill traversed the active TPC region. Measurements of the beam composition and energy are presented.

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Roy, S., R. Bandyopadhyay, Y. Yang, T. N. Parashar, W. H. Matthaeus, S. Adhikari, V. Roytershteyn i in. "Turbulent Energy Transfer and Proton–Electron Heating in Collisionless Plasmas". Astrophysical Journal 941, nr 2 (1.12.2022): 137. http://dx.doi.org/10.3847/1538-4357/aca479.

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Abstract Despite decades of study of high-temperature weakly collisional plasmas, a complete understanding of how energy is transferred between particles and fields in turbulent plasmas remains elusive. Two major questions in this regard are how fluid-scale energy transfer rates, associated with turbulence, connect with kinetic-scale dissipation, and what controls the fraction of dissipation on different charged species. Although the rate of cascade has long been recognized as a limiting factor in the heating rate at kinetic scales, there has not been direct evidence correlating the heating rate with MHD-scale cascade rates. Using kinetic simulations and in situ spacecraft data, we show that the fluid-scale energy flux indeed accounts for the total energy dissipated at kinetic scales. A phenomenology, based on disruption of proton gyromotion by fluctuating electric fields that are produced in turbulence at proton scales, argues that the proton versus electron heating is controlled by the ratio of the nonlinear timescale to the proton cyclotron time and by the plasma beta. The proposed scalings are supported by the simulations and observations.

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Li, Li-Li, Fu-Hu Liu, Muhammad Waqas, Rasha Al-Yusufi i Altaf Mujear. "Excitation Functions of Related Parameters from Transverse Momentum (Mass) Spectra in High-Energy Collisions". Advances in High Energy Physics 2020 (10.06.2020): 1–21. http://dx.doi.org/10.1155/2020/5356705.

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Transverse momentum (mass) spectra of positively and negatively charged pions and of positively and negatively charged kaons, protons, and antiprotons produced at mid-(pseudo)rapidity in various collisions at high energies are analyzed in this work. The experimental data measured in central gold-gold, central lead-lead, and inelastic proton-proton collisions by several international collaborations are studied. The (two-component) standard distribution is used to fit the data and extract the excitation function of effective temperature. Then, the excitation functions of kinetic freeze-out temperature, transverse flow velocity, and initial temperature are obtained. In the considered collisions, the four parameters increase with the increase of collision energy in general, and the kinetic freeze-out temperature appears at the trend of saturation at the top Relativistic Heavy Ion Collider and the Large Hadron Collider.

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Martiryan, D. A. "SELECTION OF COINCIDENCE ELECTRON-PROTON EVENTS IN NUCLEI INTERACTION". Proceedings of the YSU A: Physical and Mathematical Sciences 53, nr 1 (248) (15.04.2019): 53–59. http://dx.doi.org/10.46991/pysu:a/2019.53.1.053.

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The main goal of this analysis is to study momentum (or kinetic energy) distribution of the backward going protons using data from CLAS EG2 experiment at Jefferson Lab. In this experiment scattering of a 5.014 GeV electron beam off various nucleus targets, ranging from deuterium to lead, have been recorded. The analysis includes selection of events in the reaction $ A(e, e^{\prime}, P_{back}) X $, where $ P_{back} $ is a proton scattered above 90° either in the lab coordinate frame or with respect to the direction of the interacting virtual photon, then performing required corrections and studying the protons momentum distribution as a function of energy transfer. In this paper identification of electron-proton events is presented.

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Kalytka, V. A. "Nonlinear Quantum Phenomena During the Polarization of Nanometer Layers of Proton Semiconductors and Dielectrics". Izvestiya of Altai State University, nr 4(120) (10.09.2021): 35–42. http://dx.doi.org/10.14258/izvasu(2021)4-05.

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This paper investigates the influence of the structure and parameters of the degenerate quasi-discrete energy spectrum of relaxers (protons) on the mechanism of nonlinear quantum diffusion polarization in nanoscale layers of hydrogen bonded crystals (HBC) in a wide range of parameters of fields (100 kV/m - 1000 MV/m) and temperatures (0-1550 K). The temperature dependence of the quantum transparency of the parabolic potential barrier for protons in HBC is calculated using the Gibbs quantum canonical distribution for the ensemble of non-interacting protons (ideal proton gas balanced with the ions of anion sub-lattice) moving in an onedimensional potential field of a crystalline lattice (in the field of hydrogen bonds) with a zone structure distributed by energy levels. The influence of "zero" oscillations of protons on the temperature dependences of the proton subsystem kinetic coefficients in HBC is considered. It is revealed that proton tunneling influences the nonlinear space-charge polarization kinetics in HBC at high (150-550 K) and ultrahigh (550-1550 K) temperatures when crystalline layer thickness ranges from 1 to 10 nm. The results of theoretical studies (based on earlier experiments) are bound to be prospective for the prediction of HBC-class (KDP, DKDP) ferroelectrics properties, studying the second-order nonlinear optical effects of femtosecond lasers, and the development of memory cells for non-volatile high-speed memory devices.

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Sengbusch, Evan R., i Thomas R. Mackie. "Maximum kinetic energy considerations in proton stereotactic radiosurgery". Journal of Applied Clinical Medical Physics 12, nr 3 (12.04.2011): 122–31. http://dx.doi.org/10.1120/jacmp.v12i3.3533.

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Baliukin, I. I., V. V. Izmodenov i D. B. Alexashov. "Energetic pickup proton population downstream of the termination shock as revealed by IBEX-Hi data". Monthly Notices of the Royal Astronomical Society 509, nr 4 (14.12.2021): 5437–53. http://dx.doi.org/10.1093/mnras/stab3214.

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ABSTRACT Pickup protons originate as a result of the ionization of hydrogen atoms in the supersonic solar wind, forming the suprathermal component of protons in the heliosphere. While they are being picked by the heliospheric magnetic field and convected into the heliosheath, the pickup protons may suffer stochastic acceleration from the solar wind turbulence in the region from the Sun up to the heliospheric termination shock, where they can also experience shock-drift acceleration or reflection from the cross-shock potential. These processes create a high-energy tail in the pickup ion energy distribution. The properties of this energetic pickup proton population are still not well defined, in spite of the fact that they are vital for models that simulate energetic neutral atom fluxes. We consider two scenarios for the pickup proton velocity distribution downstream of the heliospheric termination shock (a filled shell with an energetic power-law tail, and bi-Maxwellian). Based on a numerical kinetic model and observations of the energetic neutral atom fluxes from the inner heliosheath by the IBEX-Hi instrument, we characterize the pickup proton distribution and provide estimations of the properties of the energetic pickup proton population downstream of the termination shock.

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Tenerani, Anna, Carlos González, Nikos Sioulas, Chen Shi i Marco Velli. "Dispersive and kinetic effects on kinked Alfvén wave packets: A comparative study with fluid and hybrid models". Physics of Plasmas 30, nr 3 (marzec 2023): 032101. http://dx.doi.org/10.1063/5.0134726.

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We investigate dispersive and kinetic effects on the evolution of a two-dimensional kinked Alfvén wave packet by comparing results from magnetohydrodynamic (MHD), Hall-MHD, and hybrid simulations of a low- β plasma. We find that the Hall term determines the overall evolution of the wave packet over a characteristic time [Formula: see text] in both fluid and hybrid models. Dispersion of the wave packet leads to the conversion of the wave energy into internal plasma energy. When kinetic protons are considered, the proton internal energy increase has contributions from both plasma compressions and phase space mixing. The latter occurs in the direction parallel to the guiding mean magnetic field, due to protons resonating at the Alfvén speed with a compressible mode forced by the wave packet. Implications of our results for switchbacks observations and solar wind energetics are discussed.

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Rozprawy doktorskie na temat "Proton kinetic energy"

Stuckey, Philip A. "Kinetic Studies and Electrochemical Processes at Fuel Cell Electrodes". Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1322675454.

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Heiske, Margit. "Modeling the respiratory chain and the oxidative phosphorylation". Thesis, Bordeaux 2, 2012. http://www.theses.fr/2012BOR21965/document.

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Mitochondria are cell organelles which play an essential role in the cell energy supply providing the universal high energetic molecule ATP which is used in numerous energy consuming processes. The core of the ATP production, oxidative phosphorylation (OXPHOS) consists of four enzyme complexes (respiratory chain) which establish, driven by redox reactions, a proton gradient over the inner mitochondrial membrane. The ATP-synthase uses this electrochemical gradient to phosphorylate ADP to ATP. Dysfunctioning of an OXPHOS complex can have severe consequences for the energy metabolism and cause rare but incurable dysfunctions in particular tissues with a high energy demand such as brain, heart, kidney and skeleton muscle. Moreover mitochondria are linked to widespread diseases like diabetes, cancer, Alzheimer and Parkinson. Further, reactive oxygen species which are a by-product of the respiratory chain, are supposed to play a crucial role in aging. The aim of this work is to provide a realistic model of OXPHOS which shall help understanding and predicting the interactions within the OXPHOS and how a local defect (enzyme deficiency or modification) is expressed globally in mitochondrial oxygen consumption and ATP synthesis. Therefore we chose a bottom-up approach. In a first step different types of rate equations were analyzed regarding their ability to describe the steady state kinetics of the isolated respiratory chain complexes in the absence of the proton gradient. Here Michaelis-Menten like rate equations were revealed to be appropriate for describing their behavior over a wide range of substrate and product concentrations. For the validation of the equations and the parameter estimation we have performed kinetic measurements on bovine heart submitochondrial particles. The next step consisted in the incorporation of the proton gradient into the rate equations, distributing its influence among the kinetic parameters such that reasonable rates were obtained in the range of physiological electrochemical potential differences. In the third step, these new individual kinetic rate expressions for the OXPHOS complexes were integrated in a global model of oxidative phosphorylation. The new model could fit interrelated data of oxygen consumption, the transmembrane potential and the redox state of electron carriers. Furthermore, flux inhibitor titration curves can be well reproduced, which validates its global responses to local effects. This model may be of great help to understand the increasingly recognized role of mitochondria in many cell processes and diseases as illustrated by some simulations proposed in this work
Les mitochondries sont l’usine à énergie de la cellule. Elles synthétisent l’ATP à partir d’une succession de réactions d’oxydo-réduction catalysées par quatre complexes respiratoires qui forment la chaîne respiratoire. Avec la machinerie de synthèse d’ATP l’ensemble constitue les oxydations phosphorylantes (OXPHOS). Le but de ce travail est de bâtir un modèle des OXPHOS basé sur des équations de vitesse simples mais thermodynamiquement correctes, représentant l’activité des complexes de la chaîne respiratoire (équations de type Michaelis- Menten). Les paramètres cinétiques de ces équations sont identifiés en utilisant les cinétiques expérimentales de ces complexes respiratoires réalisées en absence de gradient de proton. La phase la plus délicate de ce travail a résidé dans l’introduction du gradient de protons dans ces équations. Nous avons trouvé que la meilleure manière était de distribuer l’effet du gradient de proton sous forme d’une loi exponentielle sur l’ensemble des paramètres, Vmax et Km pour les substrats et les produits. De cette manière, j’ai montré qu’il était possible de représenter les variations d’oxygène, de ΔΨ et de ΔpH trouvés dans la littérature. De plus, contrairement aux autres modèles, il fut possible de simuler les courbes de seuil observées expérimentalement lors de la titration du flux de respiration par l’inhibiteur d’un complexe respiratoire donné.Ce modèle pourra présenter un très grand intérêt pour comprendre le rôle de mieux en mieux reconnu des mitochondries dans de nombreux processus cellulaires, tels que la production d’espèces réactives de l’oxygène, le vieillissement, le diabète, le cancer, les pathologies mitochondriales etc. comme l’illustrent un certain nombre de prédictions présentées dans ce travail

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Ntsendwana, Bulelwa. "Advanced low temperature metal hydride materials for low temperature proton exchange membrane fuel cell application". Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8494_1307431585.

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Energy is one of the basic needs of human beings and is extremely crucial for continued development of human life. Our work, leisure and our economic, social and physical welfare all depend on the sufficient, uninterrupted supply of energy. Therefore, it is essential to provide adequate and affordable energy for improving human welfare and raising living standards. Global concern over environmental climate change linked to fossil fuel consumption has increased pressure to generate power from renewable sources [1]. Although substantial advances in renewable energy technologies have been made, significant challenges remain in developing integrated renewable energy systems due primarily to mismatch between load demand and source capabilities [2]. The output from renewable energy sources such as photo-voltaic, wind, tidal, and micro-hydro fluctuate on an hourly, daily, and seasonal basis. As a result, these devices are not well suited for directly powering loads that require a uniform and uninterrupted supply of input energy.

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Labreuche, Pierre. "Ondes de relief dans l'océan profond : mélange diapycnal et interactions avec les oscillations inertielles". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAU035/document.

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L'Océan Austral est une zone clef pour la circulation océanique tant à cause de l'intensité du courant circumpolaire antarctique qu'en tant que région de formation des masses d'eaux abyssales de l'océan global. Pour modéliser l'océan et prévoir les changements climatiques futurs, il est important de comprendre les processus de mélange diapycnal qui lient ces eaux abyssales aux couches supérieures. Dans l'Océan Austral, des courants profonds et intenses s'écoulent sur une topographie accidentée, ce qui génère des ondes internes de relief très énergétiques. Actuellement, la dissipation de l'énergie induite par ces ondes de relief est la candidate principale pour expliquer les forts taux de mélange observés à ces latitudes. L'objet du présent travail de thèse est de comprendre comment les ondes internes de relief sont dissipées et affectent la circulation et le mélange diapycnal dans l'océan abyssal. Nous examinons l'impact de ces ondes sur le mélange profond au moyen d'une combinaison d'expertise de terrain, de simulations non hydrostatiques bi-dimensionnelles et de calculs théoriques. Sur la gamme de paramètres étudiés, nous montrons, en présence des ondes de relief, une intensification du taux de dissipation d'énergie cinétique turbulente sur une profondeur de 1000 m au-dessus de la topographie, atteignant typiquement ~20 mW/m2. Nous montrons également comment les ondes participent à des interactions triadiques impliquant des oscillations inertielles qui sont amplifiées par intéractions résonantes contrôlées par les ondes de relief. Finalement, nous préparons de futures études tri-dimensionnelles en concevant un cadre numérique et en décrivant des outils théoriques adaptés à ce problème. Nos résultats préliminaires en trois dimensions montrent qui le confinement méridien de la topographie réduit significativement l'émissions d'ondes internes de relief
The Southern Ocean plays a key role in global ocean circulation by connecting the major ocean basins with the intense Antarctic Circumpolar Current and as a formation region for abyssal water masses of the global ocean. Understanding the diapycnal mixing processes that link these abyssal waters to the overlying layers is essential both for ocean modelling and for predicting future climate change. In the Southern Ocean, deep reaching currents impinge on rough topography and create highly energetic internal lee waves. The dissipation of the energy of these internal lee waves is the main candidate for explaining the high mixing rates between waters of different densities observed at these latitudes. The purpose of this study is to understand the fate of the internal lee wave energy and how it affects the circulation and diapycnal mixing in the abyssal ocean. We first study the impact of internal lee waves on deep mixing with the combination of field expertise, two-dimensional non hydrostatic numerical simulations and theoretical developments. Over the range of parameters studied, an enhanced bottom turbulent kinetic energy dissipation is observed in the bottom 1000 m, typically reaching $sim$ 20 mW.m$^{-2}$. We further show that internal lee waves undergo non-dissipative wave-wave interactions that can be rationalized as resonant triad interactions between the bottom emitted internal lee waves, inertial oscillations and linear combinations of these two waves. We then build a three-dimensional model configuration and specific diagnostic methods that pave the way for future investigations in three dimensions. Preliminary results with the three-dimensional numerical configuration show that the meridional confinement of the topography notably reduces the emission of internal lee waves

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Jaïdane, Nejmeddine. "Etude du transfert de charge entre des atomes de soufre et des protons". Paris 7, 1987. http://www.theses.fr/1987PA077121.

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Calculs scf et ci des courbes de potentiel du systeme s+h**(+) dans les symetriplets pi et delta internenant dans la reaction, avec des orbitales moleculaires occupees representees par des orbitales atomiques polarisees et des orbitales moleculaires virtuelles donnees par la projection d'orbitales atomiques orthogonalement aux orbitales occupees. Traitement de la dynamique de l'echange de charge dans une representation diabatique ou les couplages radiaux sont nuls et l'echange de charge est induit par des couplages de type electronique. Construction d'une representation effective de dimension reduite au nombre des voies ouvertes; calcul des couplages radiaux. Resolution des equations de collision par un traitement quantique dans chaque symetrie; deduction de la constante de vitesse

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Heiske, Margit. "Modeling the respiratory chain and the oxidative phosphorylation". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16720.

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Die oxidative Phosphorylierung (OXPHOS) spielt eine zentrale Rolle im Energiestoffwechsel der Zelle. Sie besteht aus der Atmungskette, deren vier Enzymkomplexe einen Protonengradienten über die innere mitochondriale Membran aufbauen, und der ATP-Synthase, die diesen Gradienten zur Phosphorylierung von ADP zu ATP, der zelluläre Energieeinheit, nutzt. In der vorliegenden Arbeit wurde ein thermodynamisch konformes OXPHOS Modell erstellt, welches auf Differentialgleichungen basiert. Dazu wurden Gleichungen entwickelt, welche die Kinetiken jedes OXPHOS-Komplexes über weite Bereiche von Substrat- und Produktkonzentrationen sowie unterschiedlichster Werte des elektrochemischen Gradientens wiedergeben. Zunächst wurden für jeden Komplex der Atmungskette kinetische Messungen in Abwesenheit des Protonengradientens durchgeführt. Für deren Beschreibung erwiesen sich Gleichungen vom Typ Michaelis-Menten als adäquat; hierbei wurden verschiedene Gleichungstypen verglichen. Anschließend wurde der Einfluss des Protonengradientens auf die kinetischen Parameter so modelliert, dass physiologisch sinnvolle Raten in dessen Abhängigkeit erzielt werden konnten. Diese neuen Ratengleichungen wurden schließlich in ein OXPHOS Modell integriert, mit dem sich experimentelle Daten von Sauerstoffverbrauch, elektrischem Potential und pH-Werten sehr gut beschreiben ließen. Weiter konnten Inhibitor-Titrationskurven reproduziert werden, welche den Sauerstoffverbrauch in Abhängigkeit der relativen Hemmung eines OXPHOS-Komplexes darstellen. Dies zeigt, dass lokale Effekte auf globaler Ebene korrekt wiedergeben werden können. Das hier erarbeitete Modell ist eine solide Basis, um die Rolle der OXPHOS und generell von Mitochondrien eingehend zu untersuchen. Diese werden mit zahlreichen zellulären Vorgängen in Verbindung gebracht: unter anderem mit Diabetes, Krebs und Mitochodriopathien, sowie der Bildung von Sauerstoffradikalen, die im Zusammenhang mit Alterungsprozessen stehen.
Oxidative phosphorylation (OXPHOS) plays a central role in the cellular energy metabolism. It comprises the respiratory chain, consisting of four enzyme complexes that establish a proton gradient over the inner mitochondrial membrane, and the ATP-synthase that uses this electrochemical gradient to phosphorylate ADP to ATP, the cellular energy unit. In this work a thermodynamically consistent OXPHOS model was built based on a set of differential equations. Therefore rate equations were developed that describe the kinetics of each OXPHOS complex over a wide concentration range of substrates and products as well for various values of the electrochemical gradient. In a first step, kinetic measurements on bovine heart submitochondrial particles have been performed in the absence of the proton gradient. An appropriate data description was achieved with Michaelis-Menten like equations; here several types of equations have been compared. The next step consisted in incorporating the proton gradient into the rate equations. This was realized by distributing its influence among the kinetic parameters such that reasonable catalytic rates were obtained under physiological conditions. Finally, these new individual kinetic rate expressions for the OXPHOS complexes were integrated in a global model of oxidative phosphorylation. This new model could fit interrelated data of oxygen consumption, the transmembrane potential and the redox state of electron carriers. Furthermore, it could well reproduce flux inhibitor titration curves, which validates its global responses to local perturbations. This model is a solid basis for analyzing the role of OXPHOS and mitochondria in detail. They have been linked to various cellular processes like diabetes, cancer, mitochondrial disorders, but also to the production of reactive oxygen species, which are supposed to be involved in aging.

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Tippayamontri, Thititip. "Simulation Monte-Carlo de la radiolyse du dosimètre de Fricke par des neutrons rapides". Mémoire, Université de Sherbrooke, 2009. http://savoirs.usherbrooke.ca/handle/11143/4013.

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Monte-Carlo calculations are used to simulate the stochastic effects of fast neutron-induced chemical changes in the radiolysis of the ferrous sulfate (Fricke) dosimeter. To study the dependence of the yield of ferric ions, G(Fe[superscript 3+]), on fast neutron energy, we have simulated, at 25 [degree centigrade], the oxidation of ferrous ions in aerated aqueous 0.4 M H[subscript 2]SO[subscript 4] (pH 0.46) solutions when subjected to ~0.5-10 MeV incident neutrons, as a function of time up to ~50 s. The radiation effects due to fast neutrons are estimated on the basis of track segment (or"escape") yields calculated for the first four recoil protons with appropriate weighting according to the energy deposited by each of these protons. For example, a 0.8-MeV neutron generates recoil protons of 0.505, 0.186, 0.069, and 0.025 MeV, with linear energy transfer (LET) values of ~41, 69, 82, and 62 keV/[micro]m, respectively. In doing so, we consider that further recoils make only a negligible contribution to radiation processes. Our results show that the radiolysis of dilute aqueous solutions by fast neutrons produces smaller radical yields and larger molecular yields (relative to the corresponding yields for the radiolysis of water by [superscript 60]Co [gamma]-rays or fast electrons) due to the high LET associated to fast neutrons. The effect of recoil ions of oxygen, which is also taken into account in the calculations, is shown to decrease G(Fe[superscript 3+]) by about 10%. Our calculated values of G(Fe[superscript 3+]) are found to increase slightly with increasing neutron energy over the energy range covered in this study, in good agreement with available experimental data. We have also simulated the effect of temperature on the G(Fe[superscript 3+]) values in the fast neutron radiolysis of the Fricke dosimeter from 25 to 300 [degree centigrade]. Our results show an increase of G(Fe[superscript 3+]) with increasing temperature, which is readily explained by an increase in the yields of free radicals and a decrease in those of molecular products. For 0.8-MeV incident neutrons (the only case for which experimental data are available in the literature), there is a ~23% increase in G(Fe[superscript 3+]) on going from 25 to 300 [degree centigrade]. Although these results are in reasonable agreement with experiment, more experimental data, in particular for different incident neutron energies, would be needed to test more rigorously our Fe[superscript 3+] ion yield results at elevated temperatures.

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Moid, Mohd. "Proton kinetic energy anomaly, Kauzmann temperature for nanoconfined water and design of nanoscale membrane for water desalination". Thesis, 2021. https://etd.iisc.ac.in/handle/2005/5380.

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Structure, dynamics and thermodynamics of water molecules con fined inside the nanopores of various geometries are of fundamental interest owing to their potential applications in various nanofluidic devices, such as ion-selective channels, ionic transistor, sensing, molecular sieving, desalination, and blue energy harvesting. Strongly confi ned water shows strong quantum effect and others testing ground for many interesting physics not commonly found in bulk system. In this thesis, we have studied various aspects of the structure, dynamics and thermodynamics of water con fined inside nanopore of carbon nanotube (CNTs), and graphene slit-pore using atomistic molecular dynamics (MD) simulation. In particular, we have studied proton kinetic energy anomaly and anisotropy of the kinetic energy tensor, Kauzmann temperature for bulk and con ned water to understand its dimensionality dependence. Based on our current understanding of the dynamics of con fined fluid, we have also proposed design of new nanoscale membrane for desalination.

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Winkler, Kathrin. "Ultraschnelle, lichtinduzierte Primärprozesse im elektronisch angeregten Zustand des Grün Fluoreszierenden Proteins (GFP)". Doctoral thesis, 2003. http://hdl.handle.net/11858/00-1735-0000-0006-B0C1-3.

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Książki na temat "Proton kinetic energy"

Lyndon B. Johnson Space Center, red. Spacecraft solar particle event (SPE) shielding: Shielding effectiveness as a function of SPE Model as determined with the FLUKA radiation transport code. Houston, TX: National Aeronautics and Space Administration, Johnson Space Center, 2010.

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Wolf, E. L. Fusion in the Sun. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198769804.003.0004.

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Protons in the Sun’s core are a dense plasma allowing fusion events where two protons initially join to produce a deuteron. Eventually this leads to alpha particles, the mass-four nucleus of helium, releasing kinetic energy. Schrodinger’s equation allows particles to penetrate classically forbidden Coulomb barriers with small but important probabilities. The approximation known as Wentzel–Kramers–Brillouin (WKB) is used by Gamow to predict the rate of proton–proton fusion in the Sun, shown to be in agreement with measurements. A simplified formula is given for the power density due to fusion in the plasma constituting the Sun’s core. The properties of atomic nuclei are briefly summarized.

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Sherwood, Dennis, i Paul Dalby. Macromolecular conformations and interactions. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198782957.003.0025.

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As a polymer of many amino acids, any given protein can, in principle, adopt a huge number of configurations. In reality, however, the biologically stable protein adopts a single configuration that is stable over time. Thermodynamically, this configuration must represent a Gibbs free energy minimum. This chapter therefore explores how the thermodynamics and kinetics of protein folding and unfolding can be investigated experimentally (using, for example, chaotropes, heating or ligand interactions), and how these measurements can be used to enrich our understanding of protein configurations and stability.

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The effect of freeze-drying/fiber dissection technique on kinetic properties of dog skeletal muscle glycogen synthase. 1987.

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The effect of freeze-drying/fiber dissection technique on kinetic properties of dog skeletal muscle glycogen synthase. 1987.

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The effect of freeze-drying/fiber dissection technique on kinetic properties of dog skeletal muscle glycogen synthase. 1985.

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The effect of freeze-drying/fiber dissection technique on kinetic properties of dog skeletal muscle glycogen synthase. 1987.

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The effect of freeze-drying/fiber dissection technique on kinetic properties of dog skeletal muscle glycogen synthase. 1987.

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The effect of freeze-drying/fiber dissection technique on kinetic properties of dog skeletal muscle glycogen synthase. 1987.

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Części książek na temat "Proton kinetic energy"

Gutman, Menachem, Ester Nachliel i Michael Fishman. "Kinetic Analysis of Time Resolved Proton Diffusion on Phospholipid Membrane". W Ion Interactions in Energy Transfer Biomembranes, 93–103. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-8410-6_10.

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Sali, Andrej, Eugene Shakhnovich i Martin Karplus. "Thermodynamics and kinetics of protein folding". W Global Minimization of Nonconvex Energy Functions: Molecular Conformation and Protein Folding, 199–213. Providence, Rhode Island: American Mathematical Society, 1995. http://dx.doi.org/10.1090/dimacs/023/13.

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Galindo, C., M. Larsen, D. R. Ouellet, G. Maxin, D. Pellerin i H. Lapierre. "Effect of amino acid supply on whole body and tissue glucose kinetics in postpartum dairy cows". W Energy and protein metabolism and nutrition in sustainable animal production, 451–52. Wageningen: Wageningen Academic Publishers, 2013. http://dx.doi.org/10.3920/978-90-8686-781-3_168.

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Zhang, F. S., i T. R. Yu. "Reactions with Hydrogen Ions". W Chemistry of Variable Charge Soils. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195097450.003.0013.

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Hydrogen ion is one kind of cation which possesses many properties common to all cations. Hydrogen ion also has its own characteristic features which are of particular significance for variable charge soils. The interactions between hydrogen ions and the surface of soil particles is the basic cause of the variability of both positive and negative surface charges of variable charge soils. The quantity of hydrogen ions in soils determines the acidity of the soil while the acidity of variable charge soils is among the strongest in all the soils. This strong acidity of variable charge soils affects many other chemical properties of the soil. In this chapter, the basic properties of hydrogen ions will be briefly discussed. Then, the products and the kinetics of the interaction between hydrogen ions and variable charge soils will be treated. The dissociation of hydrogen ions from the surface of soil particles has already been mentioned in Chapter 2. After the dissociation of an electron, a hydrogen atom becomes a proton (H+ ion). The ionization energy of hydrogen atoms is 1310 kj mol-1, whereas those of alkali metals, Li, Na, K, and Cs, are 519, 494, 419 and 377 kj mol-1, respectively. This difference in the ionization energy between hydrogen and alkali metals indicates that protons have a particularly strong affinity for electrons. Therefore, protons are apt to form a covalent bond with other atoms by sharing a pair of electrons, or to form a hydrogen bond. Because of the absence of an electronic shell, a proton has a diameter of the order of 10-13 cm, while other ions with electronic shells generally have a diameter of the order of 10-8 cm. Because a proton is so small, it is quite accessible to its neighboring ions and molecules. Therefore, there is very little steric hindrance when protons participate in chemical reactions. The above-mentioned features of proton are the basis for its particular properties. Free proton in solution is extremely unstable because it is very active. In an aqueous solution it will react with water molecules to form a hydrated proton, H3O+.

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Wei, S., i A. W. ,. Jr Castleman. "Reaction Dynamics in Femtosecond and Microsecond Time Windows: Ammonia Clusters as a Paradigm". W Chemical Reactions in Clusters. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195090048.003.0009.

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The last decade has seen tremendous growth in the study of gas phase clusters. Some areas of cluster research which have received considerable attention in this regard include solvation (Lee et al. 1980), (Armirav et al. 1982), and reactivity (Dantus et al. 1991; Khudkar and Zewail 1990; Rosker et al. 1988; Scherer et al. 1987). In particular, studies of the dynamics of formation and dissociation, and the changing properties of clusters at successively higher degrees of aggregation, enable an investigation of the basic mechanisms of nucleation and the continuous transformation of matter from the gas phase to the condensed phase to be probed at the molecular level (Castleman and Keesee 1986a, 1988). In this context, the progressive clustering of a molecule involves energy transfer and redistribution within the molecular system, with attendant processes of unimolecular dissociation taking place between growth steps (Kay and Castleman 1983). Related processes of energy transfer, proton transfer, and dissociation are also operative during the reorientation of molecules about ions produced during the primary ionization event required in detecting clusters via mass spectrometry (Castleman and Keesee 1986b), providing further motivation for studies of the reaction dynamics of clusters (Begemann et al. 1986; Boesl et al 1992; Castleman and Keesee 1987; Echt et al. 1985; Levine and Bernstein 1987; Lifshitz et al. 1990; Lifshitz and Louage 1989, 1990; Märk 1987; Märk and Castleman 1984, 1986; Morgan and Castleman 1989; Stace and Moore 1983; Wei et al. 1990a,b). The real-time probing of cluster reaction dynamics is a facilitating research field through femtosecond pump-probe techniques pioneered by Zewail and coworkers (Dantus et al. 1991; Khundkar and Zewail 1990; Rosker et al. 1988; Scherer et al. 1987). Some real-time investigations have been performed on metal, van der Waals, and hydrogen-bonded clusters by employing these pump-probe spectroscopic techniques. For example, the photoionization and fragmentation of sodium clusters have been investigated by ion mass spectrometry and zero kinetic energy photoelectron spectroscopy in both picosecond (Schreiber et al. 1992) and femtosecond (Baumert et al. 1992, 1993; Bühler et al. 1992) time domains. Studies have also been made to elucidate the effect of solvation on intracluster reactions.

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Numata, Jorge. "Entropy and Thermodynamics in Biomolecular Simulation". W Handbook of Research on Systems Biology Applications in Medicine, 731–58. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-076-9.ch041.

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Thermodynamics is one of the best established notions in science. Some recent work in biomolecular modeling has sacrificed its rigor in favor of trendy empirical methods. Even in cases where physicsbased energy functions are used, entropy is forgotten or left “for later versions”. This text gives an overview of the utility of a more rigorous treatment of thermodynamics at the molecular level in order to understand protein folding and receptor-ligand binding. An intuitive understanding of thermodynamics is conveyed: enthalpy is the quantity of energy, while entropy stands for its quality. Recent advances in entropy estimation from information theory and physical chemistry are outlined as they apply to biological thermodynamics. The different enthalpic, entropic, and kinetic driving forces behind protein folding and binding are detailed. Finally, some medical applications enabled by an understanding of the free energy folding funnel concept are outlined, such as HIV-1 protease folding inhibitors.

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Akasaka, K., i T. Yamaguchi. "NMR Approaches to the Heat-, Cold-, and Pressure-Induced Unfolding of Proteins". W Biological NMR Spectroscopy. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195094688.003.0018.

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Proteins are unique at least in two aspects. First, the atoms constituting a protein molecule act highly cooperatively in constructing its unique folded structure. As a result, their conformational transitions also occur in a highly cooperative fashion (often following a two-state transition). Secondly, the free energy balance between the folded (native) and unfolded (denatured) conformers are surprisingly marginal (usually less than 10 kcal/mole protein), despite the fact that interactions of thousands of atoms are involved in the folding. Such unique properties have been acquired by protein molecules through a countless number of random experiments and subsequent selections during the course of evolution of life, so that to our eyes, at present, they look as if they were carefully designed by Nature. It is important to recognize that such random experiments occurred in a dominantly aqueous environment. In order to understand the underlying principles of design as generally as possible, we need, at least, to characterize the factors that contribute to (1) the stability of protein structures, (2) the structural details of the folded and unfolded conformers, and (3) the kinetics of folding and unfolding reactions. In all these, the involvement, of water has crucial importance. NMR can provide unique information not only on aspect (2) above, but on all the above aspects when used under appropriate design. In this presentation, some examples will be shown from our current research. Our daily experience in the kitchen shows that proteins are easily deformed (denatured); a boiled egg can be prepared just by heating to not more than 100°C in water. The easy deformability (which is, in fact, a global conformational transition) in aqueous environment is not merely a matter of interest in a kitchen, but is a quality of design for proteins by Nature. A global conformational transition (unfolding) of a protein molecule occurs even under physiological conditions, although infrequently, as evidenced by hydrogen exchange of peptide NH protons that are completely buried in the folded structure.

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Lohse, Martin J., Carsten Hoffmann, Viacheslav O. Nikolaev, Jean‐Pierre Vilardaga i Moritz BÜnemann. "Kinetic Analysis of G Protein–Coupled Receptor Signaling Using Fluorescence Resonance Energy Transfer in Living Cells". W Advances in Protein Chemistry, 167–88. Elsevier, 2007. http://dx.doi.org/10.1016/s0065-3233(07)74005-6.

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Krishnan, Kannan M. "Probes: Sources and Their Interactions with Matter". W Principles of Materials Characterization and Metrology, 277–344. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198830252.003.0005.

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Probes are generated using laboratory sources, or in large user facilities. Photon sources include incandescence and plasma discharge lamps. Electron beams are generated using thermionic or field-emission sources. RF plasma sources generate ions that are accelerated and used for scattering experiments. Specimens should be probed first with light, as it causes the least damage. Electron interaction with matter causes beam broadening, atomic displacements, sputtering, or radiolysis leading to mass loss and local contamination. Neutrons are heavier than electrons, penetrate more deeply in materials, and require more sample for analysis. Protons (positive charge, heavier than electrons) go a longer way in the specimen without significant broadening. Ions in solids undergo kinematic collisions with conservation of energy and momentum; they also lose energy continuously as they propagate. In the back-scattering geometry, they form important methods of Rutherford backscattering spectroscopy (RBS) and low-energy ion scattering spectroscopy (LEISS). Medium energy ions generate secondary ions by sputtering that can be analyzed by mass spectrometers to determine specimen composition (SIMS). Alternatively, its composition is analyzed (ICP-MS), by creating an aqueous dispersion and converting it to a plasma. Finally, interaction of high-energy ions with core electrons can lead to inner shell ionization and characteristic X-ray emission (PIXE).

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Nadeau, Robert. "The Old Story: Metaphysics, Mid–Nineteenth Century Physics, and Neoclassical Economics". W Rebirth of the Sacred. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199942367.003.0010.

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In economics textbooks, the nineteenth century creators of neoclassical economics theory, Stanley Jevons, Léon Walras, Francis Ysidro Edgeworth, and Vilfredo Pareto, are credited with disclosing the dynamics of market systems and transforming the study of economics into a rigorously mathematical scientific discipline. There are, however, no mentions in these textbooks, or in all but a few books on the history of economic thought, of a rather salient fact. Neoclassical economic theory was created by substituting economic constructs derived from classical economics and associated with the invisible hand for physical variables in the equations of a badly conceived and soon-to-be outmoded mid–nineteenth century theory in physics. The theory in physics that the economists used as the template for their theories was developed from the 1840s to the 1860s. During this period, physicists responded to the inability of classical physics to account for the phenomena of heat, light, and electricity with a profusion of hypotheses about matter and forces. In 1847 Hermann-Ludwig Ferdinand von Helmholtz, one of the best known and most widely respected physicists at this time, posited the existence of a vague and ill-defined energy that could unify these phenomena. This served as a catalyst for a movement called energetics, in which physicists attempted to explain very diverse physical phenomena in terms of a unified and protean field of amorphous energy. Because the physicists were unable to specify the actual character of this energy and could not be precise about what was being measured, their theories were not subject to repeatable experiments under controlled conditions. The amorphous character of energy in the physical theories also obliged the physicists to appeal to the law of conservation of energy, which states that the sum of kinetic and potential energy in a closed system is conserved. This appeal was necessary because it was the only means of asserting that the vaguely defined system described in the theory somehow remains the “same” as it undergoes changes and transformations.

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Streszczenia konferencji na temat "Proton kinetic energy"

NISHINAKA, I., K. NISHIO, M. ASAI, S. ICHIKAWA, K. TSUKADA, A. TOYOSHIMA, Y. NAGAME i in. "EXCITATION ENERGY DEPENDENCE OF FRAGMENT MASS AND TOTAL KINETIC ENERGY DISTRIBUTIONS IN PROTON-INDUCED FISSION OF LIGHT ACTINIDES". W Proceedings of the Fourth International Conference. WORLD SCIENTIFIC, 2008. http://dx.doi.org/10.1142/9789812833433_0025.

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Katukota, Shanthi P., Jianhu Nie, Yitung Chen, Robert F. Boehm i Hsuan-Tsung Hsieh. "Numerical Modeling of Electrochemical Process for Hydrogen Production From PEM Electrolyzer Cell". W ASME 2007 Energy Sustainability Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/es2007-36108.

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Numerical simulations of proton exchange water electrolysis for hydrogen production were performed for the purpose of examining the phenomena occurring within the proton exchange membranes (PEM) water splitting cell. A two-dimensional steady-state isothermal model of the cell has been developed. Finite element method was used to solve the multicomponent transport model coupled with flow in porous medium, charge balance and electrochemical kinetics. The Maxwell-Stefan equation is applied for the multi-component diffusion and convection in water distribution electrodes. The Butler-Volmer kinetic equation is used to obtain the local current density distribution at the catalyst reactive boundaries. Darcy’s law was applied for the flow of species in the porous electrodes. Parametric studies are performed based on appropriate mass balances, transport, and electrochemical kinetics applied to the electrolysis cell. There are significant current spikes present at the corners of the current collector. The current density varies significantly in the cell, being highest at the corners of the current collector. As the water on the anode side flows from the inlet to the outlet, the mass fraction of oxygen increases. This is the effect of oxygen concentration due to the effect oxidation of water. On the cathode side, as the mass fraction of water decreases there is little variation in the hydrogen mass fraction content due to the effect of hydrogen reduction.

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Meigo, Shin-Ichiro, Hiroki Matsuda, Yosuke Iwamoto, Makoto Yoshida, Shoichi Hasegawa, Fujio Maekawa, Hiroki Iwamoto, Tatsushi Nakamoto, Taku Ishida i Shunsuke Makimura. "Measurement of Displacement Cross Section for Proton in the Kinetic Energy Range from 0.4 GeV to 3 GeV". W Proceedings of the 3rd J-PARC Symposium (J-PARC2019). Journal of the Physical Society of Japan, 2021. http://dx.doi.org/10.7566/jpscp.33.011050.

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STRIGANOV, S. I. "PION YIELD STUDIES FOR PROTON DRIVER BEAMS OF 2-8 GeV KINETIC ENERGY FOR STOPPED MUON AND LOW-ENERGY MUON DECAY EXPERIMENTS". W Proceedings of the Workshop. WORLD SCIENTIFIC, 2010. http://dx.doi.org/10.1142/9789814317290_0013.

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Drochioiu, Gabi. "THE ROLE OF BACTERIORHODOPSIN IN LIGHT HARVESTING AND ATP PRODUCTION BY HALOBACTERIUM SALINARUM CELLS". W 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/6.1/s25.17.

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Halobacterium salinarum is an extremely halophilic marine Gram-negative obligate aerobic archaeon. Despite its name, this is not a bacterium, but rather a member of the domain Archaea, which lives in hypersaline lakes. Bacteriorhodopsin (BRh) is the red retinal-containing protein found in the cell membranes of H. salinarum and is considered a light-activated proton pump that transports protons across the plasma membrane. Bacteriorhodopsin photointermediates have been defined in kinetic and spectroscopic terms as BR568, K590, L550, M412, N560, and O640. We have previously shown, using the Forster cycle for BRh that its acidity increases greatly on illumination. Therefore, protons released upon illumination of the L550 intermediate with 412 nm light may not play an essential role in ATP production. Instead, the light-induced excitation energy, which represents the energy difference between the L550 and M412 states, can be used to extract an ATP molecule attached to ATP synthase. Thus, we have shown that this amount of energy corresponds to a near-infrared vibration, which is sufficient for ATP production and provides the most feasible molecular mechanism for this phenomenon. Here, we provide new evidence that protons are released due to BRh excitation, unrelated to ATP synthesis, being only a secondary phenomenon. In addition, once released from H. salinarum cells, protons should return back into the cells via ATP-synthase molecules to produce ATP. This is not possible at pH > 7.0, such as pH 9.5. However, the stability of M intermediates and ATP formation appear to be increased at higher pH values. Indeed, a spectral shift of 138 nm may be associated with an energy amount of about 17 kcal mol-1, which is enough energy to release a mole of ATP from ATP-synthase. In general, light excitation of fluorescent molecules is a phenomenon that induces a strong increase in their acidity. Recent data suggest that the chemiosmotic hypothesis put forward by Peter Mitchell to explain ATP formation in living cells is not correct, at least in terms of explaining light-induced ATP production in H. salinarum cells.

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Georgopoulos, Nikolaos G., Michael R. von Spakovsky i J. Ricardo Mun˜oz. "A Decomposition Strategy Based on Thermoeconomic Isolation Applied to the Optimal Synthesis/Design and Operation of a Fuel Cell Based Total Energy System". W ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33320.

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A decomposition methodology based on the concept of “thermoeconomic isolation” applied to the synthesis/design and operational optimization of a stationary cogeneration proton exchange membrane fuel cell (PEMFC) based total energy system (TES) for residential/commercial applications is the focus of this paper. A number of different configurations for the FC based TES were considered. The most promising set based on an energy integration analysis of candidate configurations was developed and detailed thermodynamic, kinetic, geometric, and economic models at both design and off-design were formulated and implemented. An original decomposition strategy called Iterative Local-Global Optimization (ILGO) developed in earlier work by two of the authors was then applied to the synthesis/design and operational optimization of the FC based TES. This decomposition strategy is the first to successfully closely approach the theoretical condition of “thermoeconomic isolation” when applied to highly complex, nonlinear systems. This contrasts with past attempts to approach this condition, all of which were applied to very simple systems under very special and restricted conditions such as those requiring linearity in the models and strictly local decision variables. This is a major advance in decomposition and has now been successfully applied to a number of highly complex, highly non-linear, and dynamic transportation and stationary systems. This paper presents the detailed results from one such application.

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Mughal, Pirbux, Yadong He i Ramzan Luhur. "Heat Transfer Performance Evaluation of PEMFC With Diamond-Shaped Staggered Cooling Channel". W ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-95589.

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Abstract The fossil fuel depletion and environmental pollution are global challenges. Hydrogen is one of the most abundant elements on earth. Recently, scientists and researchers are investigating water splitting to produce oxy-hydrogen for internal combustion engines. Several studies have been published where hydrogen was used to generate electricity. The proton exchange membrane fuel cell (PEMFC) is an alternative energy resource for future electric vehicles. The reaction of PEMFC includes hydrogen molecules splitting as hydrogen ions and electrons on the anode whereas proton meet with oxygen and electrons and form water and release heat on the cathode. There are several processes involved in heat generation in PEMFC such as resistance in current flow, entropic heat reaction, and irreversibility of the electrochemical reactions. The generated heat in PEMFC is removed through cooling channels. The heat transfer rate depends on thermal properties. The design of the such as polymer electrolyte membrane, catalyst layer, gas diffusion layer, and electrodes have different thermal properties which influence heat transfer. Proper thermal management is critical part of PEMFC operation. Because the efficiency of PEMFC depends on heat loss in-between critical range. In this study, a numerical approach is used to investigate heat transfer performance of a (PEMFC) cooling channel. The heat transfer rate, convective heat transfer coefficient, temperature distribution and pressure drop were evaluated in this work. All these results were carried out on, 0.2, 0.4, 0.6 0.8 and 1 kg/s of mass flow rate of coolant in the PEMFC cooling channel. Ansys Fluent is used for the numerical investigation. The diamond shape extended staggered pattern cooling channel were used in fuel cell for distributed flow. In this study, 2mm transverse pitch whereas 1mm, 1.5 mm and 2 mm longitudinal pitch with diamond shape extended in PEMFC cooling channel are used. However, design of experiments method was used to sort optimum results. The results reveal the extended staggered cooling channel improve heat transfer performance, 2mm and 1.5 mm transverse and longitudinal pitch respectively gave better heat transfer results and slightly higher pressure drops than 2mm pitch. Turbulence kinetic increases with decreasing transverse pitch and flow distribution improved with longitudinal pitch.

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Wang, Meng, Kihyung Kim, Michael R. von Spakovsky i Douglas J. Nelson. "Use of State Space in the Dynamic Synthesis/Design and Operation/Control Optimization of a PEMFC System". W ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68076.

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An often used approach to the synthesis/design optimization of energy systems is to only use steady state operation and high efficiency (or low total life cycle cost) at full load as the basis for the synthesis/design. Transient and partial load operations are considered secondarily by system and control engineers once the synthesis/design is fixed (i.e. system testing with standard load profiles). This paper considers the system dynamics from the very beginning of the synthesis/design process by developing the system using a set of transient thermodynamic, kinetic, geometric as well as cost models developed and implemented for the components of a 5 kW PEMFC (Proton Exchange Membrane Fuel Cell) system. The system is composed of three subsystems: a stack subsystem (SS), a fuel processing subsystem (FPS), and a work and air recovery subsystem (WRAS). In addition, state space is used in a looped set of optimizations to illustrate the effect of the control system on the synthesis/design optimization and to develop a set of optimal multi-input, multi-output (MIMO) controllers consistent with the optimal synthesis/design of the PEMFC system. It is shown that these MIMO controllers correspond to the ones found in a non-looped optimization in which the gains for the controllers are part of the decision variable set for the overall synthesis/design and operation/control optimization. These last set of results are then compared with the optimizations results found with the traditional approach of using a single load point in order to show the advantage of the dynamic optimization.

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Florescu, I. C., U. Krogh i J. V. Nørgaard. "Amino acid absorption kinetics in pigs fed different protein sources". W 6th EAAP International Symposium on Energy and Protein Metabolism and Nutrition. The Netherlands: Wageningen Academic Publishers, 2019. http://dx.doi.org/10.3920/978-90-8686-891-9_86.

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van der Meer, Y., A. J. M. Jansman i W. J. J. Gerrits. "Effects of sanitary status and feeding level on heat production kinetics in growing pigs". W 6th EAAP International Symposium on Energy and Protein Metabolism and Nutrition. The Netherlands: Wageningen Academic Publishers, 2019. http://dx.doi.org/10.3920/978-90-8686-891-9_105.

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