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Auswahl der wissenschaftlichen Literatur zum Thema „Partial phase change“
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Zeitschriftenartikel zum Thema "Partial phase change"
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Zálešák, Martin, Patrik Bouchal, Milan Ostrý, and Jiří Hejčík. "Experimental set up for the investigation of partial phase changes of phase change materials." EPJ Web of Conferences 264 (2022): 01049. http://dx.doi.org/10.1051/epjconf/202226401049.
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Thermal energy storage with phase change materials (PCMs) has attracted a lot of attention in the last several decades. Most PCMs do not change phase at a constant temperature but rather in a certain temperature range. It means that the PCM need to transit through its phase change temperature range to fully change phase from the solid state to the liquid state and vice-versa. The situation, in which the phase transition begins and/or ends within the phase change temperature range (in the mushy zone), is usually called a partial phase transition (or a partial phase change). The partial phase transitions occur quite often in real-life thermal energy storage systems with PCMs; especially when a PCM has a wide phase change temperature range. The behavior of PCMs during the partial phase transitions is poorly understood at the moment, because the experimental techniques used for the characterization of PCMs (such as the differential scanning calorimetry – DSC) are difficult to apply for the study of partial phase transitions. The lack of knowledge in this area influences the accuracy of phase change simulation models. The main goal of the experimental investigations, described in the paper, was to obtain data for the development of a simulation model for partial phase changes. The experimental set up for the investigation of partial phase changes of PCMs has been proposed, assembled, and the pilot measurements have been conducted. The experimental set up consists of two water storage tanks (that can be maintained at different water temperatures), a water-PCM concentric tube type heat exchanger and a data acquisition system. The water flows through the central tube of the heat exchanger while the PCM is located in the annular space of the exchanger. The water storage tanks, maintained at the temperatures within the phase change temperature range of a PCM, allow for the investigations of the heat storage cycles consisting of partial phase changes.
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Gamisch, Sebastian, and Stefan Gschwander. "Modeling of phase change hysteresis during partial phase change with the “shift”-method." Journal of Physics: Conference Series 2766, no. 1 (2024): 012231. http://dx.doi.org/10.1088/1742-6596/2766/1/012231.
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Abstract For phase change materials (PCM) a difference between melting and crystallization temperature can occur, the so-called supercooling. For numerical modelling of this hysteresis effect, phenomenological approaches based on the experimentally determined enthalpy-temperature relations for melting and crystallization can be applied. It is challenging to model the behavior for partial phase transitions. The study presents a new phenomenological method, called the “shift”-method. It is derived especially but not only for PCMs with a multistage phase change during crystallization, like it can occur for microencapsulated PCMs. The method is verified by experimental results and compared to an existing approach called “curve-scale”-method. Partial melting and crystallization processes of a PCM composite are experimentally characterized with differential scanning calorimetry (DSC). Additionally, both methods are integrated in a Dymola Modelica model of a battery cooling system with the PCM composite and validated against experimental results. The normalized mean square error is used to determine the deviation between the experiments and the two methods. It is less than 1.7 % for both methods.
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Zastawna-Rumin, Anna, Tomasz Kisilewicz, and Umberto Berardi. "Novel Simulation Algorithm for Modeling the Hysteresis of Phase Change Materials." Energies 13, no. 5 (2020): 1200. http://dx.doi.org/10.3390/en13051200.
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Latent heat thermal energy storage (LHTES) using phase change materials (PCM) is one of the most promising ways for thermal energy storage (TES), especially in lightweight buildings. However, accurate control of the phase transition of PCM is not easy to predict. For example, neglecting the hysteresis or the effect of the speed of phase change processes reduces the accuracy of simulations of TES. In this paper, the authors propose a new software module for EnergyPlus™ that aims to simulate the hysteresis of PCMs during the phase change. The new module is tested by comparing simulation results with experimental tests done in a climatic chamber. A strong consistency between experimental and simulation results was obtained, while a discrepancy error of less than 1% was obtained. Moreover, in real conditions, as a result of quick temperature changes, only a partial phase transformation of the material is often observed. The new model also allows the consideration of the case with partial phase changes of the PCM. Finally, the simulation algorithm presented in this article aims to represent a better way to model LHTES with PCM.
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Braga, Stefania, Alessandro Sanasi, Alessandro Cabrini, and Guido Torelli. "Voltage-Driven Partial-RESET Multilevel Programming in Phase-Change Memories." IEEE Transactions on Electron Devices 57, no. 10 (2010): 2556–63. http://dx.doi.org/10.1109/ted.2010.2062185.
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GOUN, A. A., and B. YA ZEL'DOVICH. "CHANGE OF PARTIAL POLARIZATION OF A BEAM UNDER PHASE CONJUGATION." Journal of Nonlinear Optical Physics & Materials 10, no. 03 (2001): 371–75. http://dx.doi.org/10.1142/s0218863501000711.
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Possible change of the polarization state in the process of propagation is considered theoretically. We were able to suggest a mechanism that allows for a very unusual behavior of the Stokes parameters of the beam. Specially arranged phase conjugation procedure yields the decrease of only one (e.g. ∣ζ3∣∝∣(∣Ex∣2 - ∣Ey∣2)∣) Stokes component, while the degrees of 45%- and circular polarization, ζ1 and ζ2, are not changing at all.
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Su, Yifang, Yihang Zhang, Kaifeng Lin, et al. "Numerical Study on Resistance Change Characteristics of Phase Change Materials." Advances in Materials Science and Engineering 2021 (July 6, 2021): 1–12. http://dx.doi.org/10.1155/2021/7934173.
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Phase change materials are a type of emerging materials whose states will change under certain conditions, which then lead to changes in resistance. To study the characteristics of the phase change materials, a numerical simulation model of the resistive change unit based on the finite element method and the classic nucleation/growth theory is established, while the partial differential equations of electricity and heat conduction and the discrete formula of the finite element are also derived. According to the phase transition process of phase change materials, a crystalline-amorphous simulation model is also proposed in this paper to simulate the electrical and thermal properties and phase transition process of the resistive change unit. Simulations of the resistance change unit under single pulses with different amplitudes and widths as well as the simulations under continuous pulses are conducted in this paper. These results verify the characteristics of resistance change and can provide references for selecting the parameters of the resistance change units.
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Stern, Keren, Nicolas Wainstein, Yair Keller, et al. "Sub-Nanosecond Pulses Enable Partial Reset for Analog Phase Change Memory." IEEE Electron Device Letters 42, no. 9 (2021): 1291–94. http://dx.doi.org/10.1109/led.2021.3094765.
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Braga, Stefania, Alessandro Cabrini, and Guido Torelli. "Experimental Analysis of Partial-SET State Stability in Phase-Change Memories." IEEE Transactions on Electron Devices 58, no. 2 (2011): 517–22. http://dx.doi.org/10.1109/ted.2010.2090157.
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Braga, Stefania, Alessandro Cabrini, and Guido Torelli. "Transient effects in partial-RESET programming of phase-change memory cells." Solid-State Electronics 65-66 (November 2011): 250–55. http://dx.doi.org/10.1016/j.sse.2011.06.026.
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Pineda-Sanchez, Manuel, Ruben Puche-Panadero, Javier Martinez-Roman, Angel Sapena-Bano, Martin Riera-Guasp, and Juan Perez-Cruz. "Partial Inductance Model of Induction Machines for Fault Diagnosis." Sensors 18, no. 7 (2018): 2340. http://dx.doi.org/10.3390/s18072340.
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The development of advanced fault diagnostic systems for induction machines through the stator current requires accurate and fast models that can simulate the machine under faulty conditions, both in steady-state and in transient regime. These models are far more complex than the models used for healthy machines, because one of the effect of the faults is to change the winding configurations (broken bar faults, rotor asymmetries, and inter-turn short circuits) or the magnetic circuit (eccentricity and bearing faults). This produces a change of the self and mutual phase inductances, which induces in the stator currents the characteristic fault harmonics used to detect and to quantify the fault. The development of a machine model that can reflect these changes is a challenging task, which is addressed in this work with a novel approach, based on the concept of partial inductances. Instead of developing the machine model based on the phases’ coils, it is developed using the partial inductance of a single conductor, obtained through the magnetic vector potential, and combining the partial inductances of all the conductors with a fast Fourier transform for obtaining the phases’ inductances. The proposed method is validated using a commercial induction motor with forced broken bars.
Dissertationen zum Thema "Partial phase change"
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Quinlan, Patrick Duane. "The development of a novel integrated collector storage solar water heater (ICSSWH) using phase change materials and partial evacuation." Thesis, Ulster University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536464.
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The Integrated Collector Storage Solar Water Heater (ICSSWH) suffers significant ambient heat loss, especially during night-time and non-collection periods, due to its combined collection and storage function. A novel ICSSWH a Double Vessel Integrated Collector Storage (DVICS) comprised of two vertical concentric metal cylinders, with the resulting annulus filled with a Phase Change Material (PCM) and partial vacuum pressure, was designed to reduce thermal storage losses without compromising energy collection. The DVICS evolved through the development of 6 fabricated prototypes, including novel pockets and cowl configurations in the annulus, a polytetrafluoroethylene (PTFE) thermal break between the inner and outer vessel, elongation of the pockets to increase heat transfer to the PCM, aluminium vessel construction, differing water return arrangements, solar collection improvements to the vessel geometry, optimised pocket locations and transparent covers with insulation. The different DVICS designs were studied experimentally using thermal simulation, solar simulation and outdoor conditions at two European locations. The highest instantaneous collection efficiency was 43% and the lowest thermal losses coefficient was 0.98 Wm-2K-1. The heat transfer mechanisms were modelled using thermal resistance networks and dimensionless analysis. In addition the practical, environmental and economic considerations are presented.
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Petrášová, Anna. "Počítačové modelování teplotní hystereze při změně skupenství." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-445463.
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This thesis deals with computer modeling of temperature hysteresis during phase change, namely complete and partial phase change. There is performed a review of methods for modeling temperature hysteresis based on the enthalpy method and the effective heat capacity method. In the case of complete phase change, there are several methods that use the effective heat capacity method, as well as the heat source method, which, on the contrary, is a certain analogy of the enthalpy method. The following are works dealing with modelling of partial phase change, the most interesting of which is due to the validation method of static hysteresis and the method designed by Bony and Citherlet. The second part of this thesis deals with the hysteresis behavior of the material with phase change, which is organic paraffin RT 27. The input data obtained by differential scanning calorimetry was converted to the dependence of the enthalpy on temperature. These curves was represented by piecewise linear function. In the case of partial phase transformations, a modeling method based on the methods proposed by Bonym and Citherlet was designed. An one-dimensional model enabling thermal simulation of the material was implemented in the MATLAB software environment. The results obtained with this simulation are finally compared with a model that does not consider thermal hysteresis.
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Ancellin, Matthieu. "Sur la modélisation physique et numérique du changement de phase interfacial lors d'impacts de vagues." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLN010/document.
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Dans le cadre du stockage de Gaz Naturel Liquéfié (GNL) dans des réservoirs flottants, tels que les méthaniers, les contraintes imposées à la cuve par le ballotement de la cargaison doivent être quantifiées. La plupart des études expérimentales ou numériques actuelles ne prennent pas en compte la possibilité de changement de phase entre le GNL et sa vapeur lors d'un impact du liquide sur la paroi. L'objectif de cette thèse est l'ajout de ce phénomène physique dans un code de mécanique des fluides numérique pour la simulation de l'impact d'une vague déferlante sur une paroi.Dans ce but, un état de l'art des différentes modélisations possibles du changement de phase en mécanique des fluides est présenté. Il a été choisi de modéliser le changement de phase entre le liquide et le gaz à une interface franche sans hypothèse d'équilibre thermodynamique à l'interface. Un système hyperbolique de lois de conservation incluant le changement de phase interfacial hors-équilibre est présenté.Deux approches sont utilisées pour la résolution numérique de ce système. La première utilise un modèle de mélange pour décrire les mailles contenant l'interface liquide-vapeur. Dans la seconde méthode, l'interface est reconstruite et évolue de manière lagrangienne. Les deux approches sont basées sur un schéma volume fini de type Roe.L'enjeu de la simulation numérique du changement de phase interfacial est la capacité du code à gérer un rapport de densité loin de 1 et une chaleur latente élevée, qui entrainent respectivement de fortes variations de pression et de température à l'interface. L'aspect thermique est le phénomène limitant dans le cadre de la simulation d'impacts de vagues avec changement de phase. Seule une fine couche limite thermique autour de l'interface tend à revenir à l'équilibre thermodynamique liquide vapeur, ce qui limite l'effet quantitatif du changement de phase<br>In the context of Liquefied Natural Gas (LNG) transportation in floating tanks, such as in LNG carriers, the constraints imposed by the sloshing of the liquid cargo on the tank have to be estimated. Most experimental and numerical studies until now do not take into account the possibility of phase change between the LNG and its vapor during the impact of liquid on the wall. The goal of this thesis is to include this physical phenomenon into a CFD code for the simulation of a breaking wave impact on a wall.A state of the art of the different modelisations of phase change in fluid mechanics is thus presented. This work focus on the modeling of phase change between the liquid and the gas at a sharp interface, without any equilibrium hypothesis. An hyperbolic system of balance laws including non-equilibrium interfacial phase change is presented.Two approaches are used to solve numerically this system. The first one relies on a mixture model for the description of the finite volume cells containing the interface, whereas in the second approach the interface is reconstructed and evolves in a lagrangian way. Both methods are based on a Roe-type finite volume scheme.The challenge of the numerical simulation of interfacial phase change is the capacity of the code to deal with density ratio far from 1 and high latent heat, as the lead to high temperature and pressure variations at the interface. The thermal aspect is the limiting phenomenon in the frame of wave impact simulation with phase change. Only a thin boundary layer around the interface tends to return to thermodynamical equilibrium, thus limiting the quantitative effect of phase change
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Kuravi, Sarada. "Numerical Study of Encapsulated Phase Change Material (EPCM) Slurry Flow in Microchannels." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4093.
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Heat transfer and flow characteristics of phase change material slurry flow in microchannels with constant heat flux at the base were investigated. The phase change process was included in the energy equation using the effective specific heat method. A parametric study was conducted numerically by varying the base fluid type, particle concentration, particle size, channel dimensions, inlet temperature, base heat flux and melting range of PCM. The particle distribution inside the microchannels was simulated using the diffusive flux model and its effect on the overall thermal performance of microchannels was investigated. Experimental investigation was conducted in microchannels of 101 [micro]m width and 533 [micro]m height with water as base fluid and n-Octadecane as PCM to validate the key conclusions of the numerical model. Since the flow is not fully developed in case of microchannels (specifically manifold microchannels, which are the key focus of the present study), thermal performance is not as obtained in conventional channels where the length of the channel is large (compared to length of microchannels). It was found that the thermal conductivity of the base fluid plays an important role in determining the thermal performance of slurry. The effect of particle distribution can be neglected in the numerical model under some cases. The performance of slurry depends on the heat flux, purity of PCM, inlet temperature of the fluid, and base fluid thermal conductivity. Hence, there is an application dependent optimum condition of these parameters that is required to obtain the maximum thermal performance of PCM slurry flows in microchannels.<br>Ph.D.<br>Department of Mechanical, Materials and Aerospace Engineering;<br>Engineering and Computer Science<br>Mechanical Engineering PhD
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Delhorme, Maxime. "Thermodynamics and Structure of Plate-Like Particle Dispersions." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00818964.
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A considerable amount of mineral particles are found to have a plate-like shape. The work in this thesis concerns theoretical investigations, using a Monte Carlo method, of the properties of such particles in aqueous solutions. The objectives were first to create a model that could capture the essential physics of clay suspensions and also to understand the role of thermodynamics in certain chemical processes. For all investigations, the results are related to experimental studies. The acid-base behavior of clays have been studied, using the primitive model, and an excellent agreement between simulated and experimental results was found. The formation of gel phases as a function of the charge anisotropy have also been investigated. Liquid-gel and sol-gel transitions are found to occur for high and moderate charge anisotropy, respectively. These transitions were also found to be size and salt dependent. In absence of charge anisotropy, a liquid-glass transition is reported. The formation of smectic and columnar liquid crystals phases with plate-like particles has been found to be favored by a strong charge anisotropy, in opposition to what was observed for nematic phases. New liquid-crystal phases were also reported. The stability and growth of nanoplatelets is discussed. It was found that the internal Coulombic repulsion could be the cause of the limited growth of C-S-H platelets. The influence of thermodynamics on the agregation mode of such platelets was also investigated
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Li, Yaofa. "Experimental studies of Marangoni convection with buoyancy in simple and binary fluids." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53893.
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The flow in a layer of volatile fluid driven by a horizontal temperature gradient is a fundamental transport model for numerous evaporative passive cooling applications. When a thin film of a volatile liquid is subject to a horizontal temperature gradient, changes in the surface tension at the free surface lead to Marangoni stresses that drive the flow. In a thicker liquid layer, the flow is also affected by buoyancy. This thesis describes experimental studies of convection driven by a combined action of Marangoni stresses and buoyancy in simple and binary volatile liquid layers confined in a sealed rectangular cavity heated at one end and cooled at the other. Experiments with varying concentrations of noncondensables (i.e., air) ca were performed to investigate their effect on the phase change and heat and mass transport.
In the simple liquid, thermocapillary stresses drive the liquid near the free surface away from the heated end. Varying ca is shown to strongly affect the stability of this buoyancy-thermocapillary flow for Marangoni numbers Ma = 290 - 3600 and dynamic Bond numbers BoD = 0.56 - 0.82: removing air suppresses transition to multicellular and unsteady flow. The results are compared with numerical simulations and linear stability analysis. In the binary liquid considered here, a methanol-water (MeOH-H2O) mixture, solutocapillary stresses drive the flow near the free surface towards the heated end. Four distinct flow regimes are identified for this complex flow driven by thermocapillarity, solutocapillarity, and buoyancy, and are summarized in a flow regime map as a function of ca and the liquid composition (MeOH concentration). At low ca, solutocapillary effects are strong enough to drive the liquid near the free surface towards the heated end over the entire liquid layer, suggesting that binary-fluid coolants could significantly reduce film dryout.
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Reinhardt, Bruno. "Compréhension et évaluation du comportement des suspensions gaz-solide à forte charge dans les techniques de séparation aéraulique." Valenciennes, 1996. https://ged.uphf.fr/nuxeo/site/esupversions/a37df539-7e5e-4347-b8e6-7f15fd2cfb0f.
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L'optimisation du fonctionnement des cyclones peut être réalisée à partir d'études expérimentales sur maquettes. La première partie traite de la similitude: des caractérisations aérodynamiques (à vide) dans deux cyclones homothétiques mettent en évidence deux types d'écoulements et une similitude partielle. Dans une seconde partie, nous exposons les résultats des mesures de vitesse et de concentration qui permettent d'analyser la structure de l'écoulement. Nous présenterons dans la dernière partie les calculs réalisés à l'aide d'un code de simulation numérique.
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Tsafack, Chetsa Ghislain Landry. "System Profiling and Green Capabilities for Large Scale and Distributed Infrastructures." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2013. http://tel.archives-ouvertes.fr/tel-00946583.
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Nowadays, reducing the energy consumption of large scale and distributed infrastructures has truly become a challenge for both industry and academia. This is corroborated by the many efforts aiming to reduce the energy consumption of those systems. Initiatives for reducing the energy consumption of large scale and distributed infrastructures can without loss of generality be broken into hardware and software initiatives.Unlike their hardware counterpart, software solutions to the energy reduction problem in large scale and distributed infrastructures hardly result in real deployments. At the one hand, this can be justified by the fact that they are application oriented. At the other hand, their failure can be attributed to their complex nature which often requires vast technical knowledge behind proposed solutions and/or thorough understanding of applications at hand. This restricts their use to a limited number of experts, because users usually lack adequate skills. In addition, although subsystems including the memory are becoming more and more power hungry, current software energy reduction techniques fail to take them into account. This thesis proposes a methodology for reducing the energy consumption of large scale and distributed infrastructures. Broken into three steps known as (i) phase identification, (ii) phase characterization, and (iii) phase identification and system reconfiguration; our methodology abstracts away from any individual applications as it focuses on the infrastructure, which it analyses the runtime behaviour and takes reconfiguration decisions accordingly.The proposed methodology is implemented and evaluated in high performance computing (HPC) clusters of varied sizes through a Multi-Resource Energy Efficient Framework (MREEF). MREEF implements the proposed energy reduction methodology so as to leave users with the choice of implementing their own system reconfiguration decisions depending on their needs. Experimental results show that our methodology reduces the energy consumption of the overall infrastructure of up to 24% with less than 7% performance degradation. By taking into account all subsystems, our experiments demonstrate that the energy reduction problem in large scale and distributed infrastructures can benefit from more than "the traditional" processor frequency scaling. Experiments in clusters of varied sizes demonstrate that MREEF and therefore our methodology can easily be extended to a large number of energy aware clusters. The extension of MREEF to virtualized environments like cloud shows that the proposed methodology goes beyond HPC systems and can be used in many other computing environments.
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BOUDJENANE, NASR EDDINE. "Ecoulement des melanges liquides-solides en conduites horizontale et verticale : perte de charge et reduction de frottement." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13148.
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Etude de la perte de charge et du mode d'ecoulement pour des melanges liquide solide en conduites horizontales et verticales. On met en evidence deux categories de particules : particules fines a ecoulement heterogene. On obtient une reduction de frottement de 45 % en ajoutant une quantite de particules fines au melange eau et grosses particules
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Nasani, Ahmad Muntaser. "Etude des phénomènes électrofluidodynamiques sur les gaz empoussiérés en écoulement turbulent : application au transport pneumatique." Poitiers, 1987. http://www.theses.fr/1987POIT2307.
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Analyse de l'influence de certains parametres sur le processus de tranfert de charges electriques au moment du contact d'une particule solide avec une plaque metallique. Etude de la charge d'impact en fonction de l'inclinaison de la plaque, de sa position et de sa charge initiale. Analyse theorique de l'ensemble des phenomenes d'ehd lies au transport pneumatique, en particulier des chutes de pression. Resultats experimentaux dans le cas de deux phases d'ecoulement : ecoulement en phase diluee et ecoulement en phase dense discontinue
Bücher zum Thema "Partial phase change"
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Sang-in, Chŏn, ред. Hanʼguk hyŏndaesa: Chinsil kwa haesŏk. Nanam Chʻulpʻan, 2005.
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Gupta, Joyeeta. Climate Change and the Future of International Order. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198828945.003.0003.
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On the basis of the scientific consensus on the dangers of climate change, this issue emerged as a partial order in the 1990s and was developed as an international regime in five phases. This chapter analyzes how the functional order evolved throughout the phases, and assesses the respective approaches, actors, and implications. Major steps for the development of the regime were the Kyoto Protocol (KP) and the Paris Agreement (PA) though the international agreements at times and the fight against climate change in general lack the full support from several key states like the USA, China, Japan, and Russia. The order lost its predictability but retains its legitimacy, leading, however, to questionable prospects on its effectiveness. Therefore, its greatest challenge may be to change the approach from international legal action to the restructuring of societies.
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Gomez Arana, Arantza. The first attempt to negotiate the association agreement. Manchester University Press, 2017. http://dx.doi.org/10.7228/manchester/9780719096945.003.0006.
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This chapter aims to explain the phase in EU-Mercosur relations which negotiated the association agreement without reaching a successful ending. Both parties developed those negotiations under the European Mercosur Interregional Cooperation Agreement (EMIFCA). It was agreed that this agreement would be carried out in two phases. The first phase related to the preparation of the ground for future negotiations by comparing standards, statistical systems, trade procedures, whilst the second phase focussed on trade liberalization. The second phase of this agreement was also focussed on the actual negotiations. In the end, both parties were unable to reach an agreement and the negotiations were stopped in October 2004. This chapter will focus on the period up until the period where the EU became set on developing a political partnership with Brazil. In doing so, this decision marked the beginning of a new stage in history of EU policy towards Mercosur. By looking at how these two parts of the policy were developed, and how far both sides went in both their statements and actions it will be possible to discuss the level of engagement on the EU side towards Mercosur. It seems that there were actors within the EU willing to both increase and decrease the level of “ambition” and “commitment”. Also, Mercosur countries helped to overcome some of the obstacles and this should be considered in order not to attribute the whole outcome solely to EU behaviour. The EU developed the association agreement towards Mercosur at this stage because of the efforts of the Commissioner in charge of the policy until 1999.
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Epstein, Ben. Political Choice. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190698980.003.0004.
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Chapter 4 explains the concept of political choice, the second and most important phase of the political communication cycle (PCC). The political choice phase is the process in which political actors choose if and when to incorporate new information and communications technologies (ICTs) into their communication strategies. This chapter details the process that political actors or organizations go through when determining whether to innovate and helps to identify characteristics of those parties that are more likely to innovate earlier than others, known as innovativeness. Political choice is the behavioral component of the political communication cycle. These innovation decisions are the primary determinants regarding if and how ICT innovations are used to change political communication activity. Therefore, political choice is the most important phase of the PCC, differentiating political communication change from social and societal communication change more broadly.
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Iliopoulos, John, and Theodore N. Tomaras. Elementary Particle Physics. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780192844200.001.0001.
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Determining the nature of matter’s smallest constituents, and the interactions among them, is the subject of a branch of fundamental physics called “The Physics of Elementary Particles” – the subject of this book. During the last decades this field has gone through a phase transition. It culminated in the formulation of a new theoretical scheme, known as “The Standard Model”, which brought profound changes in our ways of thinking and understanding nature’s fundamental forces. Its agreement with experiment is impressive, to the extent that we should no longer talk about “The Standard Model” but instead “The Standard Theory”. This new vision is based on geometry; the interactions are required to satisfy a certain geometrical principle. In the physicists’ jargon this principle is called “gauge invariance”; in mathematics it is a concept of differential geometry. It is the purpose of this book to present and explain this modern viewpoint to a readership of well motivated undergraduate students. We propose to guide the reader to the more advanced concepts of gauge symmetry, quantum field theory and the phenomenon of spontaneous symmetry breaking through concrete physical examples. The presentation of the techniques required for particle physics is self-contained, and the mathematics is kept at the absolutely necessary level. The reader is invited to join the glorious parade of the theoretical advances and experimental discoveries of the last decades which established our current view. Our ambition is to make this fascinating subject accessible to undergraduate students and, hopefully, to motivate them to study it further.
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Kumlin, Staffan, and Achim Goerres. Election Campaigns and Welfare State Change. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780198869214.001.0001.
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Abstract For over three decades, mature European welfare states have been on their way into an austerity phase marked by greater need and more insecure revenues. A number of reform pressures—including population ageing, unemployment, economic globalization, and increased migration—call into question the economic sustainability and normative underpinning of transfer systems and public services. And while welfare states long seemed resilient to growing challenges, it now seems clear that they are changing. This book examines how political leaders and the public respond to reform pressures at a pivotal moment in a mass democracy: the election campaign. Do campaigns facilitate debate and attention to welfare state challenges? Do political parties present citizens with distinct choices as to how challenges might be met? Do leaders prepare citizens for the idea that some policies may be painful? Do party messages have adaptive consequences for how the public perceives the need for reform? Do citizens adjust their normative support for welfare policies in the process? Overall, the answers to these questions affect how we understand welfare state change and the functioning of representative democracy in an era of mounting challenges. The book builds on an integrated set of data sources collected by the authors. These include information about campaign themes from a large number of countries across three decades, content analysis of party leader speeches from the largest parties in Germany, Norway, and Sweden in the 2000s, as well as experiments and panel survey data from these countries.
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Aveyard, Bob. Surfactants. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198828600.001.0001.
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Characteristically, surfactants in aqueous solution adsorb at interfaces and form aggregates (micelles of various shapes and sizes, microemulsion droplets, and lyotropic liquid crystalline phases). This book is about the behaviour of surfactants in solution, at interfaces, and in colloidal dispersions. Adsorption at liquid/fluid and solid/liquid interfaces, and ways of characterizing the adsorbed surfactant films, are explained. Surfactant aggregation in systems containing only an aqueous phase and in systems with comparable volumes of water and nonpolar oil are each considered. In the latter case, the surfactant distribution between oil and water and the behaviour of the resulting Winsor systems are central to surfactant science and to an understanding of the formation of emulsions and microemulsions. Surfactant layers on particle or droplet surfaces can confer stability on dispersions including emulsions, foams, and particulate dispersions. The stability is dependent on the surface forces between droplet or particle surfaces and the way in which they change with particle separation. Surface forces are also implicated in wetting processes and thin liquid film formation and stability. The rheology of adsorbed films on liquids and of bulk colloidal dispersions is covered in two chapters. Like surfactant molecules, small solid particles can adsorb at liquid/fluid interfaces and the final two chapters focus on particle adsorption, the behaviour of adsorbed particle films and the stabilization of Pickering emulsions.
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Mitrović, Moreno. Configurational change in Indo-European coordinate constructions. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198747307.003.0002.
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This chapter presents a case study of word order change in coordinate constructions across a wide range of Indo-European languages. Early Indo-European languages had two available patterns of coordination at their disposal: one in which the coordinating particle was placed in first and another in which it was placed in the second position with respect to the second coordinand (‘Wackernagel effect’). Diachronically, the two competing configurations reduce to a single winning one, namely the head-initial one that all contemporary Indo-European languages retained. This is accounted for as the result of the loss of ‘Wackernagel movement’ and the development of a lexicalized J(unction)-morpheme. Resting on the notion of Junction, the analysis succeeds in explaining the bimorphemicity signature of initial conjunctions by deriving the morpheme count as a fusional exponent of two functional heads. The analysis stands on the assumption that narrow- and postsyntactic processes operate in derivationally delimited chunks, qua phases.
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Josefsson, Cecilia. Defending the Status Quo. Oxford University PressNew York, 2024. http://dx.doi.org/10.1093/oso/9780197788592.001.0001.
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Abstract Defending the Status Quo explores political elites’ resistance to electoral gender quota reforms—one of the most widespread electoral reforms of recent decades—to increase understanding of the significant variation in this policy and its impact. The book conceptualizes resistance and develops an original theoretical framework for studying resistance to gender-equality policy: the resistance stage framework. Anchored in feminist institutionalism and mapped onto the policy process, it outlines how status quo defenders adapt their resistance strategies to accommodate institutional and ideational changes across agenda setting, policy formulation, decision-making, and implementation phases. The resistance stage framework is developed in conjunction with a thick description of a 30-year-long process to adopt and implement electoral gender quotas in Uruguay. While Uruguay was a vanguard in the strife for women’s rights, men’s political dominance has been pervasive in this country. The struggle to introduce a gender quota has been marked by repeated reform attempts, pervasive resistance, and a wide variation in the responses of the Uruguayan political parties, making this case apt for developing theory and shedding light on the adaptive nature of resistance. Drawing on a large number of interviews with Uruguayan political elites, three extensive quota debates, and party electoral lists, this book carefully examines the power struggle over reform in this country. It shows how powerful status quo defenders, seeking to ignore, stall, and undermine gendered institutional change, adapt their resistance strategies across different political parties and over time, as quota advocates make advances and manage to change the institutional and ideational context.
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Walsh, Bruce, and Michael Lynch. Using Molecular Data to Detect Selection: Signatures from Recent Single Events. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198830870.003.0009.
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Different types and phases of a selective sweep (hard, soft, partial, polygenic) generate different patterns of departures from neutrality, and hence require different tests. It is thus not surprising that a large number of tests have been proposed that use sequence information to detect ongoing, or very-recently completed, episodes of selection. This chapter critically reviews over 50 such tests, which use information on allele-frequency change, linkage disequilibrium patterns, spatial allele-frequency patterns, site-frequency spectrum data, allele-frequency spectrum data, and haplotype structure. This chapter discusses the domain of applicability for each test, and their strengths and weaknesses. Finally, this chapter examines application of these methods in the search for recent, or ongoing, selection in humans and for genes involved in the domestication process in plants and animals.
Buchteile zum Thema "Partial phase change"
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Kumar, D., M. Alam, and J. Sanjayan. "A Novel Concrete Mix Design Methodology." In Lecture Notes in Civil Engineering. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_46.
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AbstractConcrete mix design is the methodology for mixing binder, aggregate and water to achieve required physical, mechanical, and thermal properties. In particular, the physical properties depend on the volume fraction of each element in the concrete recipe. In this study we considered cement mortar, complying with ASTM C105, as the reference concrete with cement as the binder and silica sand as the aggregate. The reference mortar was denser with high thermal conductivity and compressive strength at given rheological properties. A denser concrete presents difficulty in material handling and imposes a safety risk, and high thermal conductivity increases building energy consumption. Therefore, lightweight concrete (LWC) has been developed by replacing silica sand with porous materials. LWC includes cement as the binder, with silica sand and other porous materials as the primary and binary fillers. The mass of the filler materials is determined by their particle density and volume fraction. LWC has low thermal mass, thereby exacerbating the summertime overheating and peak cooling demand of buildings. Therefore, there is a need to design a LWC with high thermal mass by incorporating phase change materials (PCM), which are mainly incorporated as tertiary filler. Here, we propose a novel concrete mix design methodology to incorporate PCM composite as a partial replacement of the porous material without changing binding materials.
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Voigt, Immanuel, Axel Fickert, Hajo Wiemer, and Welf-Guntram Drossel. "Experimental Investigation of Passive Thermal Error Compensation Approach for Machine Tools." In Lecture Notes in Production Engineering. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34486-2_19.
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AbstractConventional approaches to counteract thermal issues in machine tools often require a significant amount of electrical energy input, such as in active cooling systems. An energy-efficient way for reducing thermal errors is to use passive components that redistribute heat introduced by feed drives and other internal heat sources. On the one hand, latent heat storage units can be integrated into the machine to enhance the thermal stability within the phase transition temperature range of the underlying phase change material. By using latent heat storage units, the impact of highly time-varying heat flows on the thermal displacement of the tool center point can be reduced. On the other hand, passive heat-transfer devices such as heat pipes allow for an increased heat exchange within the machine tool or between the machine tool and the environment. Heat pipes exhibit a very high effective thermal heat conductivity and can be used to transfer heat from machine-internal heat sources to additionally integrated heat sinks. A compensation system is presented combining latent heat storage units and heat pipe systems. To evaluate the effect of the corresponding components on thermally induced displacements, experimental investigations of the system within a machine tool are conducted. By means of temperature and displacement measurements it is demonstrated that the proposed compensation approach allows for partial compensation of the thermal error of the machine tool.
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Meyer, Gunter H. "The Numerical Solution of Phase Change Problems." In Structure and Dynamics of Partially Solidified Systems. Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3587-7_10.
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Harikrishnan, S., and A. D. Dhass. "Effect of Particle Volume Concentration." In Thermal Transport Characteristics of Phase Change Materials and Nanofluids. CRC Press, 2022. http://dx.doi.org/10.1201/9781003163633-12.
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Steinbach, Ingo, and Hesham Salama. "Introduction." In Lectures on Phase Field. Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-21171-3_1.
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AbstractThe chapter introduces the meaning of Phase Field from the aspect of thermodynamics on the one hand and numerics of moving boundary solutions on the other hand. A moving boundary solution here means the evolution, motion, of grain boundaries, phase boundaries or surfaces in multicrystalline materials as described by a set of partial differential equations. The thermodynamic aspect relates to the concept of an order parameter, identifying a phase, in thermodynamics in general. Here the interfaces, grain- or phase boundaries and surfaces, are described by a gradient contribution in the free energy functional, the gradient of the phase field when the order changes between different grains. The history of both approaches is reviewed shortly considering their pros and cons.
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Wollkind, D. J. "Nonlinear Analyses of Phase Change and Crystal Growth Phenomena." In Structure and Dynamics of Partially Solidified Systems. Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3587-7_5.
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Joshi, C., A. Caldwell, P. Muggli, S. D. Holmes, and V. D. Shiltsev. "Outlook for the Future." In Particle Physics Reference Library. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-34245-6_12.
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AbstractThe charge separation between electrons and ions that exists within an electron plasma density wave can create large electric fields. In 1979 Tajima and Dawson first recognized that the longitudinal component of the field of a so-called “relativistic” wave (one propagating with a phase velocity close to c), could be used to accelerate charged particles to high energies in a short distance [1]. The accelerating gradient of such a plasma wave, Eo, can be approximated—assuming a total separation of electrons and ions in such a wave with wavelength λp = 2πc/ωp—as
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Bhattacharya, Rabi. "Phase Changes with Time and Multi-Scale Homogenizations of a Class of Anomalous Diffusions." In Probability and Partial Differential Equations in Modern Applied Mathematics. Springer New York, 2005. http://dx.doi.org/10.1007/978-0-387-29371-4_2.
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Robson, Robert E., Ronald D. White, and Malte Hildebrandt. "Basic Theoretical Concepts: Phase and Configuration Space." In Fundamentals of Charged Particle Transport in Gases and Condensed Matter. CRC Press, 2017. http://dx.doi.org/10.4324/9781315120935-2.
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Das, Moumita, Xingyu Tao, Yuqing Xu, and Jack C. P. Cheng. "A Blockchain-Based Secure Submission Management Framework for Design and Construction Phases." In CONVR 2023 - Proceedings of the 23rd International Conference on Construction Applications of Virtual Reality. Firenze University Press, 2023. http://dx.doi.org/10.36253/979-12-215-0289-3.32.
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AEC projects generate numerous versions of BIM models during the design and construction phases. This process is complicated by the sheer number of domains in large projects and the interlinkage of BIM deliverables (for example the structural BIM model follows the corresponding architectural BIM model). However, due to the generation of multiple versions and parallel design progress in different domains (especially in large projects), multi-domain delivery teams often fail to access and comply with the latest/required/approved design requirements during the progression of the design phase and complete issue addressing during the construction phase, which creates confusion, may lead to disputes. Moreover, due to the contractual nature of the parties involved data and process security is also very important. Therefore, this research presents blockchain-based secure coordination workflows for effective collaboration, parallel design progress, and issue management among BIM developers from multiple domains. Smart contract logic for facilitating dynamic dependency logic for coordinating linked multi-domain submission over the project timeline is presented. A method to ensure that issues are completely, and timely addressed, and related parties are held accountable for their actions or non-response is presented by integrating a BIM change identifier and blockchain in typical issue management workflows. The method considers collaborative design and issue management workflows for the secure, efficient, and complete design of BIM models. The method is validated using an ongoing large construction project in Hong Kong
Konferenzberichte zum Thema "Partial phase change"
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Krishnamurthy, Ravi M., Rudolf H. Hausler, and Samarth (Sam) Tandon. "Implications of Using the Fugacity (Activity in the Gas Phase) of the Acid Gases in the Design of Qualification Testing of Oilfield Tubular Materials." In CORROSION 2019. NACE International, 2019. https://doi.org/10.5006/c2019-12939.
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Abstract The transition from partial pressure to fugacity in the assessment of acid gas activity (concentration) for the design of qualification testing of metals to be used in sour service according to MR0175/ISO 151561,2,3 entails a number of important consequences. This transition came about in the wake of oil and gas production moving off-shore to ever higher pressures and temperatures. It was recognized that multiplying total pressure by the mol fraction of H2S in the “gas phase” could no longer reflect the physicochemical realities with respect to the reactions between H2S and the metal surfaces. As a consequence, it was proposed that the activity of H2S in the gas phase should be replaced by the activity of H2S in the aqueous phase. This change in paradigm had already been accepted in the ISO Standard but not implemented. Nevertheless, it stands to reason that the dissolved H2S is the active corrosion vector, rather than the H2S in the gas phase. An unintended consequence of this shift in thinking lies in the fact that a very large number of Heritage Metals have been qualified for partial pressure criteria as specified in MR0175/ISO-15156 by the use of the Crolet Diagram, i.e. as function of pH vs. pH2S. In order to overcome this difficulty, the H2S concentration in the solution of the test procedure used at the time is compared with the H2S concentration in solution under field conditions. It is invariably found, judging by the H2S concentration in solution, that field conditions are less aggressive than the conditions for which the test has been designed. Using a fugacity corrected Henry solubility constant ([mol/L.at]) for field conditions, together with the H2S concentration in the test solution one can determine the corresponding nominal H2S partial pressure for field conditions. One then finds that this value is higher than the one for which the test has been designed. As a practical matter, one concludes that higher grade materials, e.g. P-110 or Q-125, may be used to much higher H2S partial pressures than the ones the tests may have been designed for. For single phase system (total pressures in excess of ~ 700 bar (10,000 psi), not discussed here, a similar paradigm would hold, although based only on the equilibrium of H2S between the oil and brine phases.
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Jaeger, Paul, Luis F. Garfias-Mesias, and William H. Smyrl. "An Investigation into the Inhibition of Different VCIs for the Protection of Aluminum 2024 in the Presence of H2S and SO2." In CORROSION 1998. NACE International, 1998. https://doi.org/10.5006/c1998-98234.
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Abstract Aluminum was used to investigate the mass change associated with different Volatile Corrosion Inhibitors (VCIs) by using the Quartz Crystal Microbalance (QCM) and aluminum 2024 was characterized using a Scanning Electron Microscope (SEM). An atmosphere containing H2S, SO2, H2SO4, NH4Cl and KBr at a Critical Relative Humidity (CRH) of 80 and up to 100% and where temperatures were between 5 and 50°C was used to corrode the aluminum 2024. The SEM images of the uninhibited 2024 samples revealed a highly corroded surface, whereas the inhibited samples showed less attack after exposure to the aggressive environments. Analysis of the inclusions within the aluminum matrix showed that the addition of certain VCIs prevented attack of both the matrix and the inclusion particles (containing Mg, Mn, Fe and Cu), whereas the non-inhibited sample showed partial corrosion of the particles. The QCM data supports the data and the images taken on the SEM by showing a distinctive mass change from the adsorption of the inhibitor in the gas phase.
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Papavinasam, Sankara, Alex Doiron, and Tharani Panneerselvam. "Integration of Localized Internal Pitting Corrosion and Flow Models." In CORROSION 2012. NACE International, 2012. https://doi.org/10.5006/c2012-01262.
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Abstract A model was previously developed to predict internal pitting corrosion of oil and gas pipelines. The model considers the influence of temperature, total pressure, H2S partial pressure, CO2 partial pressure, the concentrations of sulphide, bicarbonate and chloride ions and the production rates of oil, gas, water, and solids. The model was based on experiments carried out in the laboratory at high pressure and high temperature under the operating conditions of the oil and gas pipelines and was validated by field trials and using field data. The model accounts for the statistical nature of pitting corrosion. It predicts the growth of internal pits based on readily available operational parameters from the field. The model also considers the variation of the pitting corrosion rate as a function of time and determines the precision of its prediction. Recently a microbiologically influenced corrosion (MIC) risk model has been developed and merged with the internal pitting corrosion model so that the integrated model predicts the optimized pitting corrosion rate due to both non-MIC and MIC activities. In this paper an approach was developed to integrate the internal pitting corrosion model with a flow model. The pressure drops that occur during single phase gas flow, single phase oil flow, two-phase flow and three-phase flow were calculated. Based on the pressure drop and elevation change, the pipeline locations where water and solids accumulate were estimated. The pitting corrosion rates in those locations were then predicted by superimposing the internal pitting corrosion model on the flow model. The pitting corrosion rates were further corrected to account for the variation in the field operating conditions. Though the validity of both the internal pitting corrosion model and MIC models have been individually validated using field data and the flow models have been extensively used for many years in pipeline operation, the validity of the integrated model should be evaluated before it can be used reliably.
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Hernandez Rueda, Javier, Lucas Mascaró-Burguera, Juan Ignacio Tomás Echavarría, et al. "Laser and pressure-induced phase-change transition in levitating single particle." In Ultrafast Phenomena and Nanophotonics XXIX, edited by Markus Betz and Abdulhakem Y. Elezzabi. SPIE, 2025. https://doi.org/10.1117/12.3040827.
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Braga, S., A. Sanasi, A. Cabrini, and G. Torelli. "Modeling of partial-RESET dynamics in Phase Change Memories." In ESSDERC 2010 - 40th European Solid State Device Research Conference. IEEE, 2010. http://dx.doi.org/10.1109/essderc.2010.5618176.
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Braga, Stefania, Alessand Cabrini, and Guido Torelli. "Data retention of partial-set states in phase change memories." In 2010 IEEE 3rd International Nanoelectronics Conference (INEC). IEEE, 2010. http://dx.doi.org/10.1109/inec.2010.5424897.
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Roday, Anand P., and Michael J. Kazmierczak. "Phase-Change in Finite Slabs With Time-Dependent Convective Boundary Conditions." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56734.
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The heat balance integral method is used to solve one-dimensional phase-change problem in a finite slab with time-dependent convective boundary condition, [T∞,1(t)], applied at the left face. The temperature, T∞,1(t), decreases linearly with time; the other face of the slab is subjected to a constant convective boundary condition with T∞,2 held fixed at the ambient temperature. Two initial conditions are investigated: temperature of the solid below the melting point (subcooled), and initially at the fusion temperature (Tf). The temperature, T∞,1(t) at time t = 0 is so chosen such that convective heating takes place and the slab begins to melt (i.e., T∞,1(0)> Tf> T∞,2). Thus the solid-liquid interface proceeds forward to the right. As time continues, and T∞,1(t) decreases with time, the phase-change front slows, stops, and may even reverse direction. Hence this problem features sequential melting and freezing of the slab with partial penetration of the solid-liquid front before reversal of the phase-change process. It should, however, be noted that the study is limited to only one solid-liquid interface at any given time during the phase-change process (either melting or freezing) and that slight subcooling of the melt is allowed. The effect of varying the Biot number at the right face of the slab, for both the initial conditions, is also investigated to determine its impact on the growth/recession of the solid-liquid interface. Temperature profiles in both regions (liquid and solid) are reported in detail. The effect of a slower decay rate of T∞,1(t) on the phase-change process is also analyzed for the initial condition of the slab being at the fusion temperature.
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Barz, Tilman, Aurelien Bres, and Johann Emhofer. "slPCMlib: A Modelica library for the prediction of effective thermal material properties of solid/liquid phase change materials (PCM)." In Asian Modelica Conference 2022, Tokyo, Japan, November 24-25, 2022. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp19356.
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slPCMlib predicts the effective thermal properties of solid/liquid phase change materials (PCM) showing a non-isothermal phase transition behavior. The effective properties are valid over the PCM functional temperature range where latent heat is absorbed and released. Different phenomenological phase transition models are implemented to account for temperature shifts in latent transition changes, e.g. due to multi-step transitions and thermal hysteresis. The library currently contains generic PCM and specific commercial paraffin-based and hydrated salt-based PCM (media). Its purpose is the analysis of partial and complete melting and solidification processes relevant for engineering applications, such as the design of a PCM-enhanced building components.
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Barz, Tilman, Aurelien Bres, and Johann Emhofer. "slPCMlib: A Modelica Library for the Prediction of Effective Thermal Material Properties of Solid/Liquid Phase Change Materials (PCM)." In Asian Modelica Conference 2022, Tokyo, Japan, November 24-25, 2022. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp19363.
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slPCMlib predicts the effective thermal properties of solid/liquid phase change materials (PCM) showing a non-isothermal phase transition behavior. The effective properties are valid over the PCM functional temperature range where latent heat is absorbed and released. Different phenomenological phase transition models are implemented to account for temperature shifts in latent transition changes, e.g. due to multi-step transitions and thermal hysteresis. The library currently contains generic PCM and specific commercial paraffin-based and hydrated salt-based PCM (media). Its purpose is the analysis of partial and complete melting and solidification processes relevant for engineering applications, such as the design of PCM-enhanced building components.
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Zálešák, Martin, Pavel Charvát, Lubomír Klimeš, Ondřej Pech, and Patrik Bouchal. "Thermal Behavior of PCMs During Phase Transitions With Phase Change Hysteresis: Experimental Setup Development and Problems of Model Validation." In ASME 2023 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/imece2023-113269.
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Abstract Various models and approaches for phase transitions of phase change materials (PCMs) have been proposed in recent years. However, many of these models lack validation with experimental data, particularly the models for phase change hysteresis (PCH) and incomplete (partial) phase transitions. To address this issue, an experimental setup was designed, assembled and tested for potential validation of numerical models. The experiments involve monitoring of the heat flux and the temperature distribution in a PCM contained in a rectangular cavity with a heated/cooled wall. Peltier cells are used to introduce positive or negative heat flux - heating and cooling of the PCM. The first sets of experiments were conducted with the RT35HC paraffin-based PCM. The ultimate goal of the experiments is to provide experimental data for solving inverse heat transfer problems, specifically the identification of the relationships between the enthalpy and temperature during complete and incomplete phase transitions of a PCM. The results suggest that in order to properly account for the influence of natural convection in liquid PCM, a more appropriate experimental setup that avoids its effects or a more suitable modelling approach is required.
Berichte der Organisationen zum Thema "Partial phase change"
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Delwiche, Michael, Boaz Zion, Robert BonDurant, Judith Rishpon, Ephraim Maltz, and Miriam Rosenberg. Biosensors for On-Line Measurement of Reproductive Hormones and Milk Proteins to Improve Dairy Herd Management. United States Department of Agriculture, 2001. http://dx.doi.org/10.32747/2001.7573998.bard.
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The original objectives of this research project were to: (1) develop immunoassays, photometric sensors, and electrochemical sensors for real-time measurement of progesterone and estradiol in milk, (2) develop biosensors for measurement of caseins in milk, and (3) integrate and adapt these sensor technologies to create an automated electronic sensing system for operation in dairy parlors during milking. The overall direction of research was not changed, although the work was expanded to include other milk components such as urea and lactose. A second generation biosensor for on-line measurement of bovine progesterone was designed and tested. Anti-progesterone antibody was coated on small disks of nitrocellulose membrane, which were inserted in the reaction chamber prior to testing, and a real-time assay was developed. The biosensor was designed using micropumps and valves under computer control, and assayed fluid volumes on the order of 1 ml. An automated sampler was designed to draw a test volume of milk from the long milk tube using a 4-way pinch valve. The system could execute a measurement cycle in about 10 min. Progesterone could be measured at concentrations low enough to distinguish luteal-phase from follicular-phase cows. The potential of the sensor to detect actual ovulatory events was compared with standard methods of estrus detection, including human observation and an activity monitor. The biosensor correctly identified all ovulatory events during its testperiod, but the variability at low progesterone concentrations triggered some false positives. Direct on-line measurement and intelligent interpretation of reproductive hormone profiles offers the potential for substantial improvement in reproductive management. A simple potentiometric method for measurement of milk protein was developed and tested. The method was based on the fact that proteins bind iodine. When proteins are added to a solution of the redox couple iodine/iodide (I-I2), the concentration of free iodine is changed and, as a consequence, the potential between two electrodes immersed in the solution is changed. The method worked well with analytical casein solutions and accurately measured concentrations of analytical caseins added to fresh milk. When tested with actual milk samples, the correlation between the sensor readings and the reference lab results (of both total proteins and casein content) was inferior to that of analytical casein. A number of different technologies were explored for the analysis of milk urea, and a manometric technique was selected for the final design. In the new sensor, urea in the sample was hydrolyzed to ammonium and carbonate by the enzyme urease, and subsequent shaking of the sample with citric acid in a sealed cell allowed urea to be estimated as a change in partial pressure of carbon dioxide. The pressure change in the cell was measured with a miniature piezoresistive pressure sensor, and effects of background dissolved gases and vapor pressures were corrected for by repeating the measurement of pressure developed in the sample without the addition of urease. Results were accurate in the physiological range of milk, the assay was faster than the typical milking period, and no toxic reagents were required. A sampling device was designed and built to passively draw milk from the long milk tube in the parlor. An electrochemical sensor for lactose was developed starting with a three-cascaded-enzyme sensor, evolving into two enzymes and CO2[Fe (CN)6] as a mediator, and then into a microflow injection system using poly-osmium modified screen-printed electrodes. The sensor was designed to serve multiple milking positions, using a manifold valve, a sampling valve, and two pumps. Disposable screen-printed electrodes with enzymatic membranes were used. The sensor was optimized for electrode coating components, flow rate, pH, and sample size, and the results correlated well (r2= 0.967) with known lactose concentrations.
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Choi, E., Y. I. Cho, and H. G. Lorsch. Effects of emulsifier on particle size of a phase change material in a mixture with water. Office of Scientific and Technical Information (OSTI), 1991. http://dx.doi.org/10.2172/6792238.
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Piot, Philippe. Phase-space tailoring and cooling of charged-particle beams for energy- and intensity-frontier applications. Office of Scientific and Technical Information (OSTI), 2022. http://dx.doi.org/10.2172/1887870.
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Choi, E., Y. I. Cho, and H. G. Lorsch. Effects of emulsifier on particle size of a phase change material in a mixture with water. Progress report, March 31, 1991--June 30, 1991. Office of Scientific and Technical Information (OSTI), 1991. http://dx.doi.org/10.2172/10148563.
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Lee, Wall, and Burch. PR-398-133719-R01 Inspection of Composite Repairs for Pipelines and Piping - Phase 2 NDE Trials. Pipeline Research Council International, Inc. (PRCI), 2014. http://dx.doi.org/10.55274/r0010557.
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The report reviews the research involved with Non-Destructive Examination (NDE) of composite repairs as applied to pipelines and piping. Four pipeline samples were evaluated each containing three repairs with an �open� training section and two �blind� sections (total of 12 repairs). Pipe defects included external corrosion wall loss and pitting represented by partial through-wall drilled holes. Application of the composite repairs, containing interlaminar defects and steel/composite debonding, was completed by four composite repair vendors. This included one carbon fiber and three glass fiber repair systems. The scope included an underwater repair system. Pre-hydrotest inspections were carried out between September and December 2013. Following the pre-hydrotest inspections, the samples endured static and cyclic hydrotesting. Pressure testing was done sequentially together with strain gage monitoring for three of the four samples. Acoustic emission monitoring was also performed. Static hydrotests were done to 72% and 90% SMYS with 10 minute holds in between. This was followed by cyclically testing to 10,000 cycles. Post-hydrotest inspections were done to investigate any changes that may have occurred during the hydrotests.
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Belkin, Shimshon, Sylvia Daunert, and Mona Wells. Whole-Cell Biosensor Panel for Agricultural Endocrine Disruptors. United States Department of Agriculture, 2010. http://dx.doi.org/10.32747/2010.7696542.bard.
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Objectives: The overall objective as defined in the approved proposal was the development of a whole-cell sensor panel for the detection of endocrine disruption activities of agriculturally relevant chemicals. To achieve this goal several specific objectives were outlined: (a) The development of new genetically engineered wholecell sensor strains; (b) the combination of multiple strains into a single sensor panel to effect multiple response modes; (c) development of a computerized algorithm to analyze the panel responses; (d) laboratory testing and calibration; (e) field testing. In the course of the project, mostly due to the change in the US partner, three modifications were introduced to the original objectives: (a) the scope of the project was expanded to include pharmaceuticals (with a focus on antibiotics) in addition to endocrine disrupting chemicals, (b) the computerized algorithm was not fully developed and (c) the field test was not carried out. Background: Chemical agents, such as pesticides applied at inappropriate levels, may compromise water quality or contaminate soils and hence threaten human populations. In recent years, two classes of compounds have been increasingly implicated as emerging risks in agriculturally-related pollution: endocrine disrupting compounds (EDCs) and pharmaceuticals. The latter group may reach the environment by the use of wastewater effluents, whereas many pesticides have been implicated as EDCs. Both groups pose a threat in proportion to their bioavailability, since that which is biounavailable or can be rendered so is a priori not a threat; bioavailability, in turn, is mediated by complex matrices such as soils. Genetically engineered biosensor bacteria hold great promise for sensing bioavailability because the sensor is a live soil- and water-compatible organism with biological response dynamics, and because its response can be genetically “tailored” to report on general toxicity, on bioavailability, and on the presence of specific classes of toxicants. In the present project we have developed a bacterial-based sensor panel incorporating multiple strains of genetically engineered biosensors for the purpose of detecting different types of biological effects. The overall objective as defined in the approved proposal was the development of a whole-cell sensor panel for the detection of endocrine disruption activities of agriculturally relevant chemicals. To achieve this goal several specific objectives were outlined: (a) The development of new genetically engineered wholecell sensor strains; (b) the combination of multiple strains into a single sensor panel to effect multiple response modes; (c) development of a computerized algorithm to analyze the panel responses; (d) laboratory testing and calibration; (e) field testing. In the course of the project, mostly due to the change in the US partner, three modifications were introduced to the original objectives: (a) the scope of the project was expanded to include pharmaceuticals (with a focus on antibiotics) in addition to endocrine disrupting chemicals, (b) the computerized algorithm was not fully developed and (c) the field test was not carried out. Major achievements: (a) construction of innovative bacterial sensor strains for accurate and sensitive detection of agriculturally-relevant pollutants, with a focus on endocrine disrupting compounds (UK and HUJ) and antibiotics (HUJ); (b) optimization of methods for long-term preservation of the reporter bacteria, either by direct deposition on solid surfaces (HUJ) or by the construction of spore-forming Bacillus-based sensors (UK); (c) partial development of a computerized algorithm for the analysis of sensor panel responses. Implications: The sensor panel developed in the course of the project was shown to be applicable for the detection of a broad range of antibiotics and EDCs. Following a suitable development phase, the panel will be ready for testing in an agricultural environment, as an innovative tool for assessing the environmental impacts of EDCs and pharmaceuticals. Furthermore, while the current study relates directly to issues of water quality and soil health, its implications are much broader, with potential uses is risk-based assessment related to the clinical, pharmaceutical, and chemical industries as well as to homeland security.
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Sommer, Stefan, and Andrew W. Dale. Field-experiment to determine the short-term impact of bottom trawling on the benthic ecosystem in the German coastal Baltic Sea - Cruise No. AL616, 18.07. – 09.08.2024, Kiel (Germany) – Kiel (Germany), MGF-OSTSEE-2024. GEOMAR Helmholtz Centre for Ocean Research Kiel, 2025. https://doi.org/10.3289/cr_al616.
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Within the BMBF funded second phase of the DAM project „Ausschluss mobiler grund-berührender Fischerei (MGF) in marinen Schutzgebieten der Ostsee – Phase II (MGF-Ostsee-II)“ an experimental field study has been conducted to determine the effects of bottom trawling on the benthic ecosystem of the German coastal Baltic Sea. An area characterized with low fishing activity was selected in the Mecklenburger Bight ca. 5 km north of the town Kühlungsborn based on geo-acoustic and sedimentological criteria. In a part of this area referred to as High Impact area, high intensity trawling was simulated by performing several trawls, whereas in the neighboring control area the sediments were undisturbed. Both areas were repeatedly investigated over a period of 3 weeks using biogeochemical sediment analyses, in situ benthic flux measurements and visual seafloor inspection to determine the response and changes of the benthic ecosystem to the trawling impact. Further biogeochemical analyses were conducted in sediment push cores taken by divers from specific sediment features of trawl mark tracks. In addition, physico-chemical investigations were carried out of the suspended particle plume generated during trawling as well as seafloor imaging to decipher the degree of disturbance and redistribution of sediments possibly affecting benthic communities. A total of 97 stations were sampled, including 38 MUC casts, 18 XOFOS surveys, 10 BIGO, 6 DSR and 7 CTD/water sampling rosette deployments. (Alkor-Berichte AL616)
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Lupu, Noam. Weak Parties and the Inequality Trap in Latin America. Inter-American Development Bank, 2024. http://dx.doi.org/10.18235/0012891.
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Latin America is widely acknowledged as one of the most unequal regions of the world (Sánchez-Ancochea 2021). But it is also one of the most democratic, certainly as compared to other developing regions. These two facts seem difficult to reconcile. Both folk theories of democratic representation to borrow a phrase from (Achen and Bartels 2016) and canonical models in political economy would have us believe that democracies ought to reduce inequality through redistribution (e.g., Acemoglu and Robinson 2006; Meltzer and Richard 1981; Romer 1975). As inequality increases, the proportion of the population that would benefit materially from redistribution also increases, making it more likely that a pro-redistribution political coalition would win elections and deliver social policy. And yet, despite several decades of uninterrupted electoral democracy in most of the region, Latin American governments have consistently and with but few exceptions failed to reduce inequality substantially. This paper begins by discussing why contemporary Latin American party systems are weak, focusing on both structural/institutional factors that pull party systems toward less institutionalization and recent changes to the regions political economy that undermined the more institutionalized systems. Then links the regions low levels of party-system institutionalization with lower levels of redistribution, both theoretically and empirically through cross-national comparisons. Finally, the mass and elite surveys show that legislatures in the region fail to reflect the pro-redistribution preferences of voters, further demonstrating how weak parties undermine the representation necessary for successful redistribution.
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Queiroz, Cesar, Andrés Uribe, and Dennis Blumenfeld. Mechanisms for Financing Roads: A Review of International Practice. Inter-American Development Bank, 2016. http://dx.doi.org/10.18235/0009351.
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In the last two decades there has been an increased contribution of the private sector, through some form of public-private partnership (PPP), to finance transport infrastructure in general, and roads in particular, in both the developed and developing worlds. Such contribution has helped several countries to maintain, rehabilitate and expand their road networks, including the construction of new motorways, bridges and tunnels. Some governments have increased the public contribution to potential PPP road projects to make them attractive to private investors. Such support may take the form of grants (or subsidies) to project construction, as well as availabilitypayments and operational grants or minimum revenue guarantees during the operational phase of the PPP project. Nevertheless, there are projects that will not be able to attract private financing and will have to be financed with only public funds. The main objective of this paper is to provide an overview of the most commonly used means to charge road users to generate financial resources for supporting PPP projects or to finance totally public projects. Such charges include inter alia fuel taxes, vehicle taxes, vignettes, and tolls. A brief survey of road user charging systems in selected European countries is presented. Consideration is given to different forms of PPP, including a review of potential application of the World Bank Toolkit for PPP in Roads and Highways as an instrument to help decision-makers and practitioners to define the best PPP approach for a specific country. Developing and transition economies can also take advantage of guarantees offered by international financial institutions, an example of which is the World Bank's partial risk guarantees that can increase a project's attractiveness to private investors through lower interest rates and longer maturities of loans.
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Wicker, Louise, and Nissim Garti. Entrapment and controlled release of nutraceuticals from double emulsions stabilized by pectin-protein hybrids. United States Department of Agriculture, 2004. http://dx.doi.org/10.32747/2004.7695864.bard.
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Original Objectives Specific objectives are to: (1) modify charge and hydrophobicity of pectins to improve emulsion stabilizing properties (2) develop emulsions that can be sterically stabilized using modified pectins and/or pectin/protein hybrids (3) obtain submicronal inner emulsion droplets (10-50 nanometers) with small and monodispersed double emulsion (1-2 μm) droplets with long-term stability (possibly by emulsified microemulsions) and (4) trigger and control the release at will. Background Methodology for encapsulation and controlled release of selected addenda, e.g. drugs, vitamins, phytochemicals, flavors, is of major impact in the food industries. Stable double emulsions with desired solubilization and release properties of selected addenda are formed using charge modified pectin or pectin-protein hybrids. Major conclusions, solutions, achievements * We developed methodology to isolate PME isozymes and prepared modified pectins in sufficient quantity to characterize, form single and double emulsions and test stability. *Amino acid sequence of PME isozymes was estimated and will facilitate cloning of PME for commercial application * The contribution of total charge and distribution of charge of modified pectin was determined *Soluble complexes or modified pectins and whey isolates are formed * Stable W/O/W double emulsions were formed that did not cream, had small particle size * Inner phase of double emulsions are nano-sized and stable. These new structures were termed emulsified microemulsions (EME) * Release of bioactives were controlled between a few days to months depending on layering on droplets by hybrids * Commercial testing by Israeli company of stability and release of Vitamin C showed good chemical stability Implications Resolved the major stability limitation of W/O/W emulsions. Resolved the questions regarding citrus PMEs and tailored pilot scale modification of pectins.