Top PDF Ionic charge states of solar energetic particles

Charge transport in organic solar cells

Charge transport in organic solar cells

Dispersive transport in organic semiconductors is usually thought to be caused by the energetic relaxation of hot charge carriers within their density of states [76]. Spectroscopic measurements and Monte Carlo simulations have revealed energetic re- laxation extending even to the microsecond timescales, where it could be relevant to bulk charge transport [228, 229]. Even if the bulk of the energetic relaxation were to occur on very fast timescales, there is still the question of whether residual thermal- ization might continue to long, microsecond timescales. This energetic relaxation is often understood to cause a time-dependent mobility and therefore explain dispersive current transients [217, 230], yet we will show in this chapter that this commonly-used model is inconsistent with our observations in high efficiency organic solar cell ma- terials. Instead, there is an alternative mechanism for the creation of a distribution of carrier velocities, namely, via trapping. This observation has a very direct im- pact on the numerous models, theories and experimental results describing dispersive charge transport in disordered organic semiconductors. Furthermore, it points to a new strategy for improving charge transport “management” in devices such as organic solar cells.
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Competition between the charge transfer state and the singlet states of donor or acceptor limiting the efficiency in polymer:fullerene solar cells

Competition between the charge transfer state and the singlet states of donor or acceptor limiting the efficiency in polymer:fullerene solar cells

We find that electroluminescence to be a powerful tool to study the CT state because of its ability to directly probe the interface states. Photoluminescence generally contains contributions from not separated intramolecular excitons. These contributions are strongly morphology-dependent and overlap with the intermolecular CT emission. In the case of P3HT, the contributions from component excitons even cover the CT emission completely. The EL emission, in contrast, arises from recombination at the polymer:fullerene interface. 17 This implies that singlet states visible in EL must be populated either through energy transfer from the CT state or through charge transfer from one component to the other. It is not possible, however, to distinguish these two different mechanisms within our experiment. Morteani et al. have studied polymer:polymer blends and have shown with temperature- dependent measurements that energy transfer from the CT state dominates below 4V, with an endothermic activation energy of 200 meV ± 50 meV. 51–53 Since all of the presented EL spectra have been measured at voltages smaller than 4 V, this would suggest that the principal mechanism is energy transfer from the CT state to a component singlet. The activation energy of 200 meV corresponds to about twice the width of the density of states (DOS) of an organic semiconductor, 54 which may suggest that singlet emission is linked to an overlap of CT state emission and singlet absorption. Activation might also be facilitated by the increased energetic disorder of fullerene multiadducts 55 that broaden the DOS and can ease activation.
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Cosmic ray and solar energetic particle flux in paleomagnetospheres

Cosmic ray and solar energetic particle flux in paleomagnetospheres

genic nuclides in the atmosphere are produced by alpha par- ticles and heavier cosmic rays (McCracken, 2004). At iden- tical rigidity values, protons and alphas follow the same tra- jectories whereas identical kinetic energies in general yield different orbits. More specifically, for a given rigidity, it is the ratio of charge and atomic mass that determines the cut- off energy. This ratio is unity for a proton but approximately 0.5 for all other fully ionized nuclei, so we can consider al- pha particles as representatives for the latter class of cosmic rays. The relationship between rigidity and kinetic energy is discussed in more detail by McCracken (2004) and by Vogt et al. (2007). For the proton kinetic energy levels used in this study, the associated rigidity values and kinetic ener- gies of alpha particles are given in Table 1 and Fig. 2.
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Observation of solar energetic particle (SEP) events associated with narrow CMEs

Observation of solar energetic particle (SEP) events associated with narrow CMEs

In the second event, on 1 May 2000, GOES detected an X-ray flare of class M1.1, which started at 10:16 UT and lasted for 18 min. Flare acceleration in low corona for SEPs have been suggested in many studies, showing that this event is 3 He-rich, heavy ion-rich, and shows energy-dependent heavy ion charge states, suggesting charge stripping during acceleration in a dense environment at low altitudes in the corona, much below 2 Rs (Mason et al., 2002; Klein and Pos- ner, 2005; Kartavykh et al., 2007). However, later, LASCO observed a CME, with an angular width of 54 ◦ , linear ve- locity of 1360 km s −1 and acceleration of − 62.6 km s −2 at 10:54 UT at 5.58 R at central position angle 323
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Organic solar cells : Novel materials, charge transport and plasmonic studies

Organic solar cells : Novel materials, charge transport and plasmonic studies

I would like to thank the Electronics and Mechanical Workshop at the Physics Department. Namely Chris Booth and Mark Ross for the help with many electrical circuits and equipments and David Steven for the fabrication of sample holders and other lab tools. Additionally I want to thank Steven Balfour and Callum Smith for running the clean room and Scott Johnston for his help with orders. An essential contribution to this work also comes from other members of the group. I would like to thank: Dr. Calvyn Howells for sharing his great knowledge in organic solar cells and the good times we had, experimenting in the solar cell lab. Dr. Ashu Bansal for his advice on all experimental as- pects, which were always very welcome due to his great experience in the labs and also for his ad- vice how to organise projects and papers. Dr. Alex Ward for the collaboration on the Advanced Ma- terials paper. Dr. Gordon Hedley, Dr. Arvydas Ruseckas and Scott Pearson for very helpful discus- sions about fluorescence quenching and charge recombination. Dr. Yue Wang and Dr. Emiliano Rezende-Martins for help with the AFM and SEM. Iain Robertson for helpful discussions about solvent additives in polymer blends. Finally all other group members for their individual help and insightful discussions at journal club.
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Maximum Power Point Technique based Solar Charge Controller implemented Solar System

Maximum Power Point Technique based Solar Charge Controller implemented Solar System

Muhammad Riazul Hamid.et.al [5] In this work to keep the design simple we have used Arduino Nano. It has features like: LCD display, Led Indication and it is equipped with various protections to protect the circuitry from abnormal condition. This design is suitable for a 50W solar panel to charge a commonly used 12V lead acid battery. As the maximum power point (MPP) of photovoltaic (PV) power generation systems change with changing atmospheric conditions (e.g. solar radiation and temperature), an important consideration in the design of efficient PV systems is to track the MPP correctly. We have implemented the most common MPPT algorithm named Perturb and Observe (PO) to control the output of a synchronous buck-converter.
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Energy States of Particles with Representational Spin

Energy States of Particles with Representational Spin

In any system N-particles with spin we will assign values. Those values will be relative to the system we are working with. We will assign +1 for spin up, and values −1 for spin down in a spin one half system. +1, 0, −1 for a spin one system, and ± 3 , ± 1 for a spin 3/2 system. The magnetism number will be achieved by virtue of the magnetism operator S.

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The Simulation of Ionic Charge Transport in Biological Ion Channels: an Introduction to Numerical Methods

The Simulation of Ionic Charge Transport in Biological Ion Channels: an Introduction to Numerical Methods

ening, angular deformations, bond rotational barriers, etc. that are included in the potential energy functions used to describe the molecules under study. Force field parametrization is usually performed in a way that accounts for the average effects of the atomic polarization field, and involves a redistribution of the electric charge. In other words, the simulated particles (ions and atoms or groups of atoms in the protein and in the membrane) are assigned effective properties such as charge, size, and hardness, which normally depend on their position within the system. These force field parameters [165] are optimized in such a way that the simulation reproduces some of the desired bulk properties of the solution. The idea of the parameterization is to include the effects of the true many-body polar interactions in a simple pairwise additive fashion, so that the many-body effects can be embedded implicitly in the equations for the short range force. This approach is efficient from a computational viewpoint, but it involves a few problems. First the parametrization is not unique [138]. Second, the effects of the real polarization fields are assumed to be fixed rather than consistently evolving with the charge distribution. Finally, the effects of polar- ization on the molecular flexibility are necessarily neglected. It is safe to assume that in narrow pores the polarization field plays some role in the structural prop- erties of the protein, and plays a crucial role in the ion-water and ion-protein interactions. One can try to address the problem by treating the polarization field macroscopically, i.e. by computing an effective position-dependent dielec- tric tensor at equilibrium [143], and then use this dielectric tensor in Brownian dynamics or in an appropriately modified parametrization of molecular dynam- ics. This approach, however, neglects the transient dynamics of the polarization fields that may assist permeation and selectivity in ultra-narrow channels.
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AN ENERGETIC VARIATIONAL APPROACH TO MATHEMATICAL MODELING OF CHARGED FLUIDS: CHARGE PHASES, SIMULATION AND WELL POSEDNESS

AN ENERGETIC VARIATIONAL APPROACH TO MATHEMATICAL MODELING OF CHARGED FLUIDS: CHARGE PHASES, SIMULATION AND WELL POSEDNESS

Traditionaly, (1.1)-(1.5) are posed in a fixed domain. In this work we couple equations (1.1)-(1.5) with the Allen-Cahn equation as a diffuse formulation of a moving boundary interface. The boundary interface partitions the domain into a region where the dynamics of the charge system are seperated from the other region. As is the case with many interface boundary systems, the modeling of boundary kinetics becomes difficult due to the mixing of coordinate systems. This problem is especially apparent when the interface is free to move or the functions defined over the regions separated by the interface are coupled through boundary condition. In electrolyte systems especially, many experimental observations have yet to be recovered by correct boundary kinetic formulations. A major focus of studies in electrolyte research attempts to understand the interface boundary condition coupling of the diffuse charged bodies and electrostatic potential. From a theoretical standpoint, the interface also represents a difficulty in the existence and regularity theory. The authors demonstrated in [48] that without the presence of an interface, the system (1.1)-(1.5) is totally dissipative. The presence of a boundary, however, introduces terms which are not amenable to producing apriori estimates. The reader should understand that this irrespective of the zero Debye length limit and is a misfeature of the PDE.
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Relation between Solar Flares, Halo and Partial Halo Coronal Mass Ejections, and Solar Energetic Particle Events

Relation between Solar Flares, Halo and Partial Halo Coronal Mass Ejections, and Solar Energetic Particle Events

Several studies indicate the role of solar flares and interplanetary shock waves due to CMEs in producing SEPs. Sun is an efficient particle accelerator and hence governs the energetic particles in the solar system. SEPs with energies from few 10s of keV to few GeV are accelerated near the Sun. They are classified into two different types of events (i) impulsive events and (ii) gradual events. The acceleration of electrons and charged nuclei to high energies is a phenomenon occurring at many astrophysical sites throughout the universe. In the heliosphere, processes in the solar corona associated with flares and coronal mass ejections (CMEs) are the most energetic natural particle accelerators, sometimes accelerating electrons and ions to relativistic energies (Droge 2003) 1 .The gradual SEP events cause high risk to the health of humans in space and in future colonies of humans on other planets within the solar system since they accompany very high energies (> 10s of MeV). They are also hazardous to spacecraft. The understanding of this gradual SEP events can be found in (Desai and Geacalone) 2 .
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MPPT Technique based Hybrid Solar Charge Controller

MPPT Technique based Hybrid Solar Charge Controller

MPPT technique is a technique used in a solar charge controller to track the maximum power in the PV (Photovoltaic) array by changing the duty cycle of the converter subsequently even under low sunlight condition. The controller after a voltage sensor checks the output voltage from the panel and performs the MPPT technique. Based on irradiations from the sun and the output from the panel, the relay switches between the buck converter and boost converter and charges the battery at its safest charging voltage (24 volts).

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Energetic Valorization of Adrar City Step Sludge by Batch Solar Digester

Energetic Valorization of Adrar City Step Sludge by Batch Solar Digester

Abstract-- This work studies a novel digester using only solar energy, which presents a good environment and economic solution, especially in remote Saharan areas of ALGERIA. The produced batch solar digester treats the purification plant sludge of ADRAR natural lagoon located in western south of ALGERIA (1500 km from the capital of' ALGERIA). The solar collector incorporated in the digester converts the collected solar energy into thermal energy; this last is used to warm the digester. The period of experimentation was done during the months of autumn and winter when it was cold ambient temperatures. The temperature interval ensured by the solar collector supports a maximum methanization during an important delay of the day inside the digester. This methanization starts the flammable biogas production from the 20 th day. Then, the digestate can be used also as fertilizer for the Saharan arable lands poor in organic matter.
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Single Phase Solar Inverter with Smart Charge Control

Single Phase Solar Inverter with Smart Charge Control

With this mind-set, this paper aims to design, build, and test a solar panel inverter with thermo electric generator to convert waste heat in to electricity. This inverter system could be used as backup power during outages, battery charging, or for typical household applications. The key features of the system are a true 50Hz, 230V RMSoutput voltage, a wide input range, an intelligent charger and a power output for led lamps. The overall goal is to design this system while minimizing component costs. Although systems with similar features already exist, many are prohibitively expensive. In addition, inverters in the lower price range typically lack the features mentioned above. Hence the main aim of the proposed work lies in designing a solar panel inverter that is flexible and utilizes a wide range of input voltage range for various photovoltaic panels. Also, the proposed scheme is said to provide a charge control option that makes optimal use of any solar panel.
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Theory of the charge recombination reaction
rate in dye sensitised solar cells

Theory of the charge recombination reaction rate in dye sensitised solar cells

As mentioned earlier, these theoretical approaches lack a full quantum mechanical description of the electrons involved, although tunnelling can be introduced in an ad hoc fashion [68]. To fully assess the impact of structural changes to the dye molecule, a full quantum description has to be invoked. This can be achieved by several quantum dynamics schemes developed over the years that can describe accurately fast electron transfer processes. In many cases the time-dependent population of the initial state is obtained by wavepacket propagation under a model Hamiltonian [69], parameterised with computational data or with experimental input [70]. Nuclear vibrational modes can be treated [71], although only a low-order polynomial expansion of the coupling matrix elements of the acceptor’s and donor’s states around the equilibrium geometry has been implemented in practice. Other studies include the presence of the semi-infinite semiconductor surface through a Green’s function formalism [70, 72], which operates on diabatic states pertaining to different partitions of the overall system. The (electronic) coupling between the semiconductor and molecule subsystems thus introduced quantifies the interaction between them and triggers the charge transfer process.
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Energetic neutral atom fluxes from the heliosheath varying with the activity phase of the solar cycle

Energetic neutral atom fluxes from the heliosheath varying with the activity phase of the solar cycle

In our hydrodynamical model, called the Bonn model, a consistent coupling of five different fluids, namely protons, H-atoms, PUI’s, anomalous cosmic rays (ACR’s) and galac- tic cosmic rays (GCR’s) is treated. This model which orig- inally was run for stationary boundary conditions more re- cently has also been used to treat time-dependent boundary conditions by Scherer and Fahr (2002, 2003a,b), primarily for the purpose to study time-variabilities of the heliospheric interface under the action of solar cyclically variable inner boundary conditions due to the periodically variable inner solar wind ram pressure. This advanced modelling of the interface shall now also be used here to deliver the hydrody- namic properties of protons and PUI’s at all places of the in- ner and outer heliosphere at all events of time during consec- utive solar cycles. With these properties made available we then start to calculate the originating time-dependent ENA fluxes according to the method described below.
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Charge Distribution of Fine and Ultrafine NaCl Aerosol Particles by Tandem DMA Technique

Charge Distribution of Fine and Ultrafine NaCl Aerosol Particles by Tandem DMA Technique

A DMA operates by balancing the electrical force on a charged particle in an applied electric field, with the drag force on the particle as it moves through the fluid. DMA consists of a cylindrical central electrode and coaxially aligned cylindrical stainless steel housing. Filtered, dry air is supplied in the annular region around the central electrode, and an annular flow of sampled aerosol is introduced from the top of the DMA column. Aerosol is normally passed through a radioactive ionizing source, to give a known charge level to the particles. Aerosol particles enter the DMA in a thin annular ring adjacent to the outer cylinder, and the charged particles are attracted or repelled by the potential on the central rod. Near the end of the central rod is a slit through which particles of the desired electric mobility pass, while particles of higher electric mobility (smaller and/or more highly charged) hit the central rod upstream of the sample slit and particles of lower electric mobility (larger and/or uncharged) pass out of the DMA through the excess output air flow.
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The solar energetic particle event of 2010 August 14: connectivity with the solar source inferred from multiple spacecraft observations and modeling

The solar energetic particle event of 2010 August 14: connectivity with the solar source inferred from multiple spacecraft observations and modeling

This SEP event was associated with a fast halo CME observed by the Large Angle and Spectrometric Coronagraph ( LASCO ) on board SOHO ( Brueckner et al. 1995 ) that had a plane-of-sky speed of 1205 km s − 1 and was fi rst seen at 10:12 UT in the C2 coronagraph with a leading edge distance of 2.92 R e ( as reported in the SOHO / LASCO CME catalog at cdaw.gsfc.nasa.gov / CME_list /) . The SEP event was also associated with a GOES C4.4 fl are that started at 09:38 UT ( e.g., Richardson et al. 2014; Gopalswamy et al. 2015; Park et al. 2015 ) . Park et al. ( 2015 ) located the fl are at N17 ° W52 ° , while Gopalswamy et al. ( 2015 ) placed it at N12 ° W56 ° , both assigning it to NOAA Active Region ( AR ) 11099. On the other hand, Tun & Vourlidas ( 2013 ) , Bain et al. ( 2014 ) , and Liewer et al. ( 2015 ) associated it with AR 11093. In fact, AR 11099 was a new active region that appeared late on 2010 August 13 after the initially single sunspot of AR 11093 separated into two spots, helping to account for the uncertainty in the AR assignment. Tun & Vourlidas ( 2013 ) and Liewer et al. ( 2015 ) concluded that the associated CME was generated by the western portion of a sigmoidal fi lament southwest of the NOAA AR 11093 with a location in H α of N13 ° W54 ° ( Carrington Longitude 351 °) . Our own identi fi cation using 193 Å images collected by the Atmospheric Imaging Assembly ( AIA; Lemen et al. 2012 ) of the Solar Dynamics Observatory ( SDO; Pesnell et al. 2012 ) agrees with this site of the solar eruption, which we therefore use in this study; the longitude is indicated by the straight purple line in Figure 1 ( a ) . We fi nd no evidence that the widespread SEP event on 2010 August 14 might have involved more than one near-simulta- neous solar events ( e.g., “ sympathetic fl ares ”) at widely separated locations, based on examination of EUV and white- light ( WL ) observations made by the STEREO and near-Earth spacecraft. These observations show no other eruptions or CMEs consistent with the time of the event.
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Paralytic hypo energetic state facilitates anoxia tolerance despite ionic imbalance in adult Drosophila melanogaster

Paralytic hypo energetic state facilitates anoxia tolerance despite ionic imbalance in adult Drosophila melanogaster

When metazoans are broadly considered, it is clear that anoxia tolerance can be achieved without preservation of near-normoxic ATP levels, contrary to the paradigm for anoxia-tolerant vertebrates such as turtles and carp. Here we have identified that survival from anoxic exposure in D. melanogaster is associated with maintenance of extremely low but non-zero ATP levels, likely made possible by behavioral paralysis that reduces metabolic rate and use of diverse metabolic pathways to generate ATP anaerobically. Additionally, we show that surviving anoxia in D. melanogaster adults is related to the ability to tolerate large disturbances in extracellular ionic homeostasis. Given the many similarities in response to anoxia with mammals, identification of the molecular and cellular mechanisms that allow D. melanogaster to survive low energetic state and large ionic disruptions may be useful for advancing the understanding of variation in anoxia tolerance in a biomedical context.
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Synthesis of 3-D coronal-solar wind energetic particle acceleration modules

Synthesis of 3-D coronal-solar wind energetic particle acceleration modules

The Coronal-Solar Wind Energetic Particle Acceleration (C-SWEPA) modeling effort in the NASA/NSF Space Weather Modeling Collaborative [Schunk, 2014] combines two successful Living With a Star (LWS) (http://lws. gsfc.nasa.gov/) strategic capabilities: the Earth-Moon-Mars Radiation Environment Modules (EMMREM) [Schwadron et al., 2010] that describe energetic particles and their effects, with the Next Generation Model for the Corona and Solar Wind developed by the Predictive Science, Inc. (PSI) group. The goal of the C-SWEPA effort is to develop a coupled model that describes the conditions of the corona, solar wind, coronal mass ejections (CMEs) and associated shocks, particle acceleration, and propagation via physics-based modules. Assessing the threat of SEPs is a dif fi cult problem. The largest SEPs typically arise in conjunction with X class fl ares and very fast ( > 1000 km/s) CMEs. These events are usually associated with complex sunspot groups (also known as active regions) that harbor strong, stressed magnetic fi elds. Highly energetic protons generated in these events travel near the speed of light and can arrive at Earth minutes after the eruptive event. The generation of these particles is, in turn, believed to be primarily associated with the shock wave formed very low in the corona by the passage of the CME (injection of particles from the fl are site may also play a role). Whether these particles actually reach Earth (or any other point) depends on their transport in the interplanetary magnetic fi eld and their magnetic connection to the shock.
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