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Dissertations / Theses on the topic 'Ion current'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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1

Johansson, Morgan. "Ion current interface." Thesis, Linköping University, Department of Electrical Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4000.

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Abstract The reason to measure the ion current in a combustion engine is to extract combustion parameters in order to achieve closed loop control of the combustion i.e. control of the spark, fuel and air into the engine. By using the spark plug, in a spark-ignited engine, as a probe it is possible to measure the ion current.

The purpose with this thesis is to improve an existing ion current interface.

A ringing caused by the ignition coil will follow by the ion current signal. Now the need of energy in the spark increase. Since increased energy in the spark gives a longer burn time and a longer ringing the ringing will extend into the ion current signal. The problem with the old interface is that the ringing is not symmetrical which could cause problems when filtering the signal.

The aim of this thesis is to achieve a symmetrical ringing and a interface that can handle an ion current amplitude from 0,1µA to 1mA.

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2

Nilsson, Johan. "AC Ion Current Interface." Thesis, Karlstad University, Division for Engineering Sciences, Physics and Mathematics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-3473.

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An effective way to extract combustion parameters from a spark ignited engine is to measure the level of ionization. One way to do this is to use the spark plug as a sensor.

Until now this has been achieved by applying a DC voltage over the spark gap which causes an electrical field. The electrical field together with the ionization process gives cause to an ion current which can be measured and analyzed. Previous research suggests that it would be beneficial to replace the DC voltage with an AC voltage.

The focus in this thesis is on the hardware and how to best implement an AC voltage to the existing ion sensing system. Both simulation- and hardware models will be constructed. These models will be tested and analyzed to evaluate both benefits and drawbacks of an AC ion current sensing system.

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3

Forster, David Robert. "Ring current ion populations during geomagnetically disturbed periods." Thesis, Aberystwyth University, 2011. http://hdl.handle.net/2160/5864b468-d9e7-462f-be82-a9b130b1004f.

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Charge exchange is investigated as a source of magnetospheric He+ . Ionic data from the Magnetospheric Ion Composition Spectrometer (MICS) on the Combined Release and Radiation Effects Satellite (CRRES) are investigated during storm and quiet periods. A He+ /He++ maximum is observed at Ring Current altitudes, where particle trapping is relatively stable. A study of ionic number density across the main and recovery phases of geomagnetic storms provides evidence of a recovery phase source of He+ that does not include the other species. It is suggested that charge exchange of trapped He++ ions with exospheric neutral hydrogen is the source of this He + . Cross sections are obtained for the He++ He+ charge exchange reaction. A new population of He+ ions is observed within the drift echo of an injection which occurred during orbit 497 of CRRES, at E/q values not present in the injection. The possibility of this new He+ population having arisen due to charge exchange is discussed, and charge exchange cross sections are calculated for the reaction. The cross sections calculated for these data are larger than those found by previous work, and it is concluded that the observed effect cannot be explained entirely by charge exchange. Solar wind precursors to pseudobreakups are compared to those of substorms. [Tsurutani et al., 2003] gave examples of stormtime periods which did not contain substorm expansion phases. These are investigated for evidence of electron injections at geosynchronous altitude. It is shown that injections did occur during these periods, though generally at lower energy than those with expansions. The injections are attributed to pseudobreakup activity rather than full substorms. Solar wind parameters are compared to injection energy for storms with expansions and without. It is shown that the occurrence of expansions is associated with spikes in solar wind density, though a time lag of up to 20 minutes is required. This is explained in relation to the pressure catastrophe ([Erickson and Wolf, 1980]), whereby some time is required for magnetospheric convection.
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4

Gustafsson, Karin. "Ion Current Dependence on Operating Condition and Ethanol Ratio." Thesis, Linköping University, Department of Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8053.

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This masters thesis investigates the possibility to estimate the ethanol content in the fuel using ion currents. Flexible fuel cars can be run on gasoline-ethanol blends with an ethanol content from0 to 85 percentage. It is important for the engine control system to have information about the fuel. In todays cars the measurements of the fuel blend are done by a sensor. If it is possible to do this with ion currents this can be used to detect if the sensor is broken, and then estimate the ethanol content until the sensor gets fixed. The benefit

of using ion currents is that the signal is measured directly from the spark plug and therefore no extra hardware is needed. To be able to see how the ethanol ratio affects the ion currents, the dependencies of the operating point have been investigated. This has been done by a literature review and by measurements in a Saab 9-3. Engine speed, load, ignition timing, lambda and spark plugs effects on the ion currents are especially studied. A black box model for the ion currents dependence on operating point is developed. This model describes the engine speed, load and ignition timing dependencies well, but it can not be used to estimate the ethanol ratio.

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5

Carlsson, Johan. "Ion cyclotron resonance heating and current drive in tokamaks /." Stockholm : Tekniska högsk, 1998. http://www.lib.kth.se/abs98/carl0424.pdf.

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6

Winch, Tom J. "Current based models for Markov ion channel gating mechanisms." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311750.

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7

Vadivelu, Sunilkumar. "Investigation of sinusoidal ripple current charging techniques for Li-ion cells." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-195169.

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In recent years, the demand for Li-ion-type batteries has been increasing significantly in various fields of applications including portable electronics, electric vehicles, and also in renewable energy support. These applications ask for a highly efficient charging strategy in order to maintain a long life cycle of the batteries. Recently, a new charging technique referred as sinusoidal ripple current-constant voltage charging (SRC-CV) technique has been proposed and is in certain publications claimed to realize an improved charging per-formance on Li-ion batteries than conventional constant-current constant-voltage charg-ing (CC-CV) techniques. In this thesis, the charging performance of the SRC-CV charging method applied to a prismatic Li-ion cell for an automotive traction application is inves-tigated. An existing experimental setup is upgraded to realize charging of the Li-ion cells using the SRC-CV charging method. Electrochemical impedance spectrums of three Li-ion cells have been obtained using electrochemical impedance spectroscopy (EIS). These spectrums were used to determine the charging ripple-current frequency where the mag-nitudes of the ac impedance of the cell are minimized. Key parameters like charging time, discharging time, and energy efficiency are calculated in order to compare the charg-ing performance of the CC-CV and SRC-CV charging techniques. The results reported from the experimental results obtained in this thesis indicate that there is no significant improvement with the SRC-CV charging method (implemented using a constant ripple-current frequency) compared to the CC-CV method in terms of charging time and energy efficiency.
På senare tid har behovet av batterier av Li-jontyp ökat kraftigt inom ett flertal applikationsområden inkluderande portabel elektronik, elfordon och miljövänlig elenergiproduktion. I dessa applikationsområden behövs en högeffektiv laddstrategi för att möjliggöra ett stort antal cyklingar av batterierna. Nyligen har en new laddmetod, benämnd sinusoidal ripple current-constant voltage-laddning (SRC-CV-laddning) föreslagits och har i vissa publikationer demonsterat en förbättring av laddprestanda hos Li-jonbatterier jämfört med konventionell constant-current constant-voltage-laddning (CC-CV-laddning). I detta examensarbete undersöks laddprestandan hos SRC-CV och CC-CV-laddning när de appliceras på prismatiska Li-jonceller avsedda för traktionsdrift. En existerande experimentuppsättning har uppgraderats för att realisera laddcykling med SRC-CV-laddning. Med hjälp av elektrokemisk impedansspektroskopi på tre Li-jonceller har den frekvens vid vilken magnituden på cellernas impedans är minimerad identifierats. Nyckelparametrar såsom laddtid, urladdningstid och energieffektivitet har uppmätts för både SRC-CV- och CC-CV-laddning. De experimentella resultaten visar ingen signifikant förbättring mellan SRC-CV-laddning (implementerat med en konstant rippelströmfrekvens) och konventionell CC-CV-laddning.
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8

Xing, Hanwen, and Xin Liu. "A Lithium-ion Battery Charger." Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-44826.

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Nowadays personal small electronic devices like cellphones are more and more popular, but the various batteries in need of charging become a problem. This thesis aims to explain a Lithium-ion charger which can control the current and voltage so that it can charge most kinds of popular batteries. More specifically, Li-ion battery charging is presented. The charging circuit design, simulation and the measurements will also be included.
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9

Toida, M., T. Maeda, I. Shiiba, A. Sugishima, and Y. Ohsawa. "Simulation studies of heavy ion heating by current-driven instabilities." American Institute of Physics, 2000. http://hdl.handle.net/2237/7011.

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10

Stok, Andrew. "Lateral current injection s-laser with ion-implanted lateral heterobarriers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/MQ49752.pdf.

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11

Premanode, Bhusana. "Current-mode readout toplogies for ion-sensitive field effect transistors." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500038.

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12

Fok, Chi Wah Eddie. "Simulation of lithium-ion batteries based on pulsed current characterization." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58720.

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Simulation of lithium-ion and other cells is important for basic understanding, design of cells, application in devices including automotive, and as part of system simulations for control and safety purposes. This thesis proposes a new cell equivalent circuit model, called the distributed state of charge model, which consists of a series resistance, and a non-linear RC transmission line. The circuit model components are dependent on the SOC, with the circuit being unique in considering the local (depth dependent) charge state. A pulsed discharge and charge technique is put forth for extracting the model parameters, and their dependence on cell state of charge. The extraction method is applied to commercial lithium-ion cells. It is shown that the extracted parameters are largely independent of magnitude of the pulsed currents. This distinguishes the model from other widely used equivalent circuits in which parameter extraction is generally performed as a function of current. Therefore, this approach is promising for reducing time required for this extraction phase. Validation experiments are performed using both static discharge and a variable-current profile. Two versions of the model are developed based on the governing diffusion mechanism – planar or spherical. Simulations using the planar model matched experimental results well for large current pulses (up to 2.0 C discharge) with slow average discharge (0.20 C discharge) – root-mean-square error typically within 0.84%, and maximum error within 3.7%. On the other hand, the spherical model performs well for higher continuous discharge current (up to 0.50 C discharge), but for lower current pulses (up to 0.67 C discharge) – root-mean-square error typically within 0.95%, and maximum error within 3.3%. This tradeoff may be attributed to the distribution of capacitances in the corresponding electrode models. Parameters of the proposed equivalent-circuit are also extracted for a lithium-alloying tin electrode. Tin is an electrode of interest due to its high specific and volumetric capacity. The response is much different from those obtained from the commercial lithium ion cells, including apparent drops in effective diffusion coefficient by three orders of magnitude over narrow regions of SOC. These characteristics are explained qualitatively using the phase transformation effect.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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13

Djekanovic, Nikolina. "Design of Resonant Filters for AC Current Magnification : Heating of Li-ion Batteries by Using AC Currents." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-247892.

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Using alternating current in order to heat batteries at sub-zero temperatures is a method,which is investigated in-depth by an increasing number of study groups. The thesis considersthe resonance phenomenon with the intention to use alternating current amplificationand battery’s impedance in order to induce power dissipation inside the battery, and in thisway increase its temperature. A battery cell is thereby modelled as an impedance transferfunction, estimated from electrochemical impedance spectroscopy measurements, whichare taken for a LiNi 13Mn13Co13O2 cell. Note that at 1 kHz and room temperature (20 ◦C),the ohmic resistance of the selected cell amounts to only 0.76m. Five resonant circuitsare investigated and one of them is selected for further investigation, and as a basis for afilter design. The chosen resonant circuit lead to an LCL filter with current magnification.The experimental setup used for conducting practical experiments, offers the possibilityof operating the voltage source converter both as a Full-bridge and as a Half-bridge, withand without current control. For each possible configuration, an LCL filter and a currentcontroller are designed, taking into account the corresponding limitations in frequency,current and controller voltage. The filter design is based on a multiobjective optimizationmethod used to determine filter components that yield the highest gain value for everyconfiguration. The method minimizes two objective functions in order to find an optimalsolution. The first objective is the reversed absolute value of the gain, whereas thesecond one is the absolute impedance of the circuit, consisting of the filter and batterycells. The gain is thereby defined as the ratio between the induced cell current and thecurrent entering the circuit. The obtained results of the proposed method are experimentallyvalidated. Depending on how the filters were physically designed and taking intoaccount the corresponding voltage source converter configuration, gains of 16 were experimentallyachieved. Finally, the three investigated configurations are compared againstthe reference case (Half-bridge voltage source converter with current control and a singleinductor) regarding their power efficiencies. The power measurements showed that despitehigh obtained gains, the overall filter power losses remained approximately in thesame range, compared to the power losses of the reference case. This is due to the factthat stray resistances of the designed LCL filters easily reached values of around 40m,which hindered an efficient power transfer with the chosen voltage source converter andthe used battery cells. This further indicates the importance of building filters with lowstray resistances and in this thesis, it represents a primary source of improvement.
Användandet av växelströ m fö r att värma upp batterier är en metod som fö r närvarande undersö ks av ett flertal forskargupper. Detta examensarbete fokuserar kring hur resonans kan nyttjas fö r att ö ka strö mfö rstärkningen och, pådetta sätt, ö ka effektutvecklingen i batteriet (av LiNi1/3Mn1/3Co1/3O2-typ). Battericellens impedans modelleras som en ö verfö ringsfunktion vars parametrar estimerats från tidigare genomfö rda impedansspektroskopimätningar. Vid 1 kHz och rumstemperatur är den cellens ohmska resistansen endast 0.76 mΩ. Fem mö jliga resonanta kretsar har undersö kts och en av dem valts ut fö r vidare undersö kningar. The utvalda kretsen är ett LCL-filter med vilken strö mfö rstärkning åstadkoms. Den experimentella uppställningen, i vilken praktiska test har genomfö rts, medger mö jligheten att nyttja den tillhö rande omriktaren både som en helbrygga och en halvbrygga, med och utan strö mreglering. Fö r varje mö jlig omriktarkonfiguration har ett LCL-filter och en strö mreglering tagits fram, med hänsyn tagen till uppställningens begränsningar i termer av frekvens, strö moch dc-spänningsnivå. Filtren är framtagna med hjälp av en multiobjektiv optimering vilken åstadkommer hö gsta strö mfö rstärkning mö jlig fö r varje omriktare och strö mregleringsval. Metoden minimerar tvåfunktioner fö r att finna en optimal lö sning. Den fö rsta funktionen beskriver inversen påströ mfö rstärkningen och den andra lastens (bestående av filter och tillhö rande battericell) impedans absolutbelopp. Den resulterande ö har validerats experimentellt och en strö mfö rstärkningsnivåpå 16 uppnåddes. Slutligen har de olika konfigurationerna jämfö rts i termer av verknings-grad. De genomfö rda effektmätningarna visar att trots att hö ga strö mfö rstärkningsnivåer var mö jliga såresulterade de associerade filterfö rlusterna till liknande verkningsgrader fö r alla studerade konfigurationer. Resultaten understryker fö rdelarna med hö geffektiva filtervilka representerar en mö jlig väg fö r vidare undersö kningar.
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14

Garg, Vivek. "Regulation of ATP-Sensitive Potassium Channels in the Heart." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1238179085.

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15

Zicha, Stephen. "Molecular basis for ion current heterogeneity in normal and diseased hearts." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85660.

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Cardiac action potential characteristics are known to vary in different species, but also in the different regions of the heart within a given species and in cardiovascular disease. The heterologous expression of voltage-gated ion currents is believed to underlie these differences. The purpose of this thesis is to elucidate the molecular mechanisms which may underlie some of the observed current changes in different species, as well as regions and diseases of the heart.
Here, we describe the variable dependence on repolarizing K+ currents in different species as being the result of the lack of Ito subunits in guinea pig heart with a greater expression of IK subunits, while rabbits express all hypothesized Ito subunits, but express IK subunits at low levels. Humans are found to lie in between these two species in terms of the expression of these voltage-gated K+ channel subunits. The specialized function of certain regions of the heart, such as the ventricles and the SAN, have been attributed to the heterologous expression of Ito and the pacemaker current (I f) respectively. Here were demonstrate that both Kv4.3 and KchIP2 gradients underlie an observed Ito transmural gradient and contribute to the dispersion of repolarization, while a greater expression of HCN2 and HCN4 subunits in the SAN compared to the right atrium account for the larger I f current in this region. Cardiovascular diseases such as congestive heart failure (CHF) have been associated with ion channel remodelling. Here, we report the finding of changes in Nav1.5, Kv4.3, HCN2 and HCN4 expression which may underlie some of the electrophysiological changes associated with this disease. Furthermore, we characterise a genetic polymorphism which is associated with another disease, atrial fibrillation.
The heterologous expression of voltage-gated ion channel subunits may account for many of the species-, region- and disease-specific differences which have been observed in the heart. Such heterogeneity contributes to the proper functioning of the heart under normal conditions, but may also contribute to the pathogenesis of cardiovascular disease.
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16

Panousakis, Dimosthenis. "Ion current sensing for controlled auto ignition in internal combustion engines." Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/8145.

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Envirom-nental pollution is a subject that needs urgent addressing. Since the internal combustion engine has its fair share of accountability on this, research on techniques for increasing engine efficiency and emissions is necessary. Controlled Auto Ignition is a promising combustion mode, which increases fuel efficiency while also reducing NOx emissions to negligible levels. This Thesis concentrates on the implementation of this mode through experimental research, on an engine equipped with a fully variable valvetrain. Investigation of the operational window, emissions, fuel consumption, thermodynamic efficiency is carried out and ways to improve on these are discussed. The governing consideration, however, is the control method for this rather intricate combustion mode. As such, experimental data acquisition and analysis of ion current under the whole operating spectrum, from spark ignition to full autoignition is made. It is found that the expected gains in fuel consumption and emissions are realized. In addition, ion current proves to be a very powerful and cost effective tool for engine monitoring, diagnosis and control. The author concludes that Controlled Auto Ignition is a viable proposition for mass production engine designs and that ion current, although not absolutely vital for engine control, considerably increases engine control thus allowing for greater operating window under autoignition, without compromising reliability or cost.
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17

Penache, Dan Lucius. "Heavy ion beam transport in laser initiated high current gas discharge channels." Phd thesis, [S.l.] : [s.n.], 2002. http://elib.tu-darmstadt.de/diss/000245.

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18

Rojko, Roman. "New concepts for transverse beam stability in high-current heavy-ion synchrotrons." Phd thesis, Berlin : Dissertation.de, 2003. http://elib.tu-darmstadt.de/diss/000382.

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19

Main, Daniel S. "Multi-ion plasma processes in the low altitude auroral upward current region." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3207758.

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20

Hannan, Abdul. "Modelling Ion Cyclotron Resonance Heating and Fast Wave Current Drive in Tokamaks." Doctoral thesis, KTH, Fusionsplasmafysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119930.

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Fast magnetosonic waves in the ion cyclotron range of frequencies have the potential to heat plasma and drive current in a thermonuclear fusion reactor. A code, SELFO-light, has been developed to study the physics of ion cyclotron resonantheating and current drive in thermonuclear fusion reactors. It uses a global full wave solver LION and a new 1D Fokker-Planck solver for the self-consistent calculations of the wave field and the distribution function of ions.In present day tokamak experiments like DIII-D and JET, fast wave damping by ions at higher harmonic cyclotron frequencies is weak compared to future thermonuclear tokamak reactors like DEMO. The strong damping by deuterium, tritium and thermonuclear alpha-particles and the large Doppler width of fast alpha-particles in DEMO makes it difficult to drive the current when harmonic resonance layers of these ionspecies are located at low field side of the magnetic axis. At higher harmonic frequencies the possibility of fast wave current drive diminishes due to the overlapping of alpha-particle harmonic resonance layers. Narrow frequency bands suitable for the fast wave current drive in DEMO have been identified at lower harmonics of the alpha-particles. For these frequencies the effect of formation of high-energy tails in the distribution function of majority and minority ion species on the current drive have been studied. Some of these frequencies are found to provide efficient ion heating in the start up phase of DEMO. The spectrum where efficient current drive can be obtained is restricted due to weak electron damping at lower toroidal mode numbers and strong trapped electron damping at higher toroidal mode numbers. The width of toroidal mode spectra for which efficient current drive can be obtained have been identified, which has important implications for the antenna design.

QC 20130327

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Mann, William. "Using ion current to probe nanostructured battery materials in different oxidation states." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10155543.

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Ionic currents were used to probe amorphous MnO

2

, which is a battery cathode material in lithium ion batteries, that was template electrodeposited in polycarbonate cylindrical nanopores. The porous MnO

2

occupies the volume extending approximately 1 μm into the pore from one end and nanovoid channels, in the MnO

2

, allow for electrolyte solution to pass through from one end to the other.

Presented in this thesis are the results of ionic current studies used to probe ion transport through amorphous MnO

2

, in different oxidation states, with 100 mM LiClO4 electrolyte in propylene carbonate (PC) solvent. Current-voltage curves, from ionic current-measurements, were unable to resolve excess surface charge in the electrodeposited MnO

2

. A comparison of current-voltage curves from when the MnO

2

was cycled between lithium inserted and deinserted oxidation states showed a trend of increasing resistance over a series of three lithium insertion and deinsertion cycles.

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Lindqvist, Daniel. "Simulation of Intermittent Current Interruption measurements on NMC-based lithium-ion batteries." Thesis, Uppsala universitet, Strukturkemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325298.

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The objective of this report was to implement battery cycling and an intermittent current interruption (ICI) method for determining battery resistance into a simple lithium-ion battery model in the finite element methods (FEM) program COMSOL Multiphysics, andevaluate how accurately the model reflects the behaviour of voltage and internal resistance with respect to experimental results. The ICI technique consists of repeating the steps of first having a longer charging period and then having a short current interruption, where the internal resistance is calculated from the voltage drop that occurs when the current is turned off. The model was evaluated against measurements, made with the same technique (ICI), on assembled NMC-graphite batteries. Codes written in the statistical programming language “R” were used to process the data from both COMSOL and the experiments. Both the batteries and the model were constructed with a reference electrode, to enable measurement of each electrode by itself. The results as documented in this report show that it is possible to simulate the measurement technique in COMSOL, but that both the resistance and voltage profiles differed quite a lot from the behaviour of the tested batteries. The resistance of the positive electrode did however give good results and it was possible to improve the model by changing some parameters. The magnitude of the resistance, which was already quite close, could be improved by changing the porosity and particle size, and the voltage profiles were improved when using voltage-data achieved from the real measurements.
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Fiala, J. "Investigation of space charge neutralization effects in high-current positive ion beams." Thesis, University of Salford, 2008. http://usir.salford.ac.uk/26675/.

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Through the experience gained during the industrial development of low energy implanters, it is commonly believed that improvements in forced space-charge neutralization are responsible for the maintenance of high currents down to an energy of about 3 keV. However, despite major improvements in plasma flood neutralizer design, drift mode currents below this energy are still too low to have the same performance as obtained in accel/decel (A/D) mode. It has become clear that neither the nature of neutralization process nor the role of the "so called" beam plasma that is created in the beam environment are fully understood. The work presented was carried out on the PLUTO ion implanter beamline at the University of Salford fitted with a high density (HD) plasma flood source (PFS). The beam and flood plasmas were studied independently prior to the investigation of the coupled system. Langmuir probe measurements have been carried out on 1-10 keV Ar + beams at the wafer position in the PLUTO machine, which is a specially adapted version of a commercial ion implanter (Applied Materials xR LEAP). The main parameters of the beam plasmas, electron and ion densities, electron temperatures, and plasma and floating potentials have been measured as functions of beam energy, beam current, beam-line pressure and beam tuning settings. It has been found that in common with the plasmas in ion source and plasma flood plasmas, the electrons in the beam plasma are characterized by two temperatures. All plasma parameters depend critically on the details of the tuning parameters and the beamline pressure. The PFS plasma using mainly Xe was studied and the two operational modes (A/D and BIAS) compared. The results from mass energy analyser suggest that the plasmas are very similar after correcting the plasma potentials for the different electrical setups. When the ion implanter and the PFS are operated simultaneously, the beam current transmitted to the wafer changes in a manner that depends on the operating conditions (ion beam current, PFS arc voltage, PFS arc current, PFS gas flow rates). This dependence is the strongest when the A/D mode is used, due to the presence of a positive potential close to the ion beam.
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Kurian, Febin [Verfasser], Peter [Akademischer Betreuer] [Gutachter] Hülsmann, and Oliver [Gutachter] Kester. "Cryogenic current comparators for precise ion beam current measurements / Febin Kurian ; Gutachter: Peter Hülsmann, Oliver Kester ; Betreuer: Peter Hülsmann." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2015. http://d-nb.info/1125525681/34.

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25

Sridhar, Arun. "Regulation of cardiac voltage gated potassium currents in health and disease." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1186603836.

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Holmberg, Madeleine. "Determination of Solar EUV Intensity and Ion Flux from Langmuir Probe Current Characteristics." Thesis, Uppsala University, Department of Physics and Astronomy, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-114460.

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This report presents a model to determine the solar Extreme UltraViolet (EUV) intensity and the ion flux in the vicinity of Saturn, by using measurements from the Langmuir probe, a plasma investigation instrument, of the Cassini satellite. The model is based on in situ measurements and does therefore provide an improved estimation of the wanted parameters compared to previously used calculations based only on the EUV flux measured near Earth. The solar EUV and ion flux were determined by analysing and processing the current measurements from the Cassini Langmuir probe in several steps. Initially the time intervals where the measured current were expected to be due only to the photoelectron current was extracted. The photoelectron current is the part of the measured probe current that is only due to electrons ejected from the probe by photons coming from the Sun. The measurements showed a periodic behaviour which was concluded to be due to the attitude of the satellite. This interfering effect was corrected for and the data was then plotted against an EUV index, estimated from a traditionally used proxy of the EUV flux near Earth; the F10.7 solar radio flux index. In agreement with the theory of the photoelectric effect a linear relationship between the EUV flux and the photoelectron current mph was expected. A least square linear fit to the extracted photoelectron current data provided the relation, for the Langmuir probe on Cassini, in the form of the equation mph=0.1842EUV+0.2405, where mph is the photoelectron current in nA and EUV is the EUV index in W/Hzm^2. The derived equation is the result of the study, showing how to estimate the solar EUV flux using the Langmuir probe current measurements. This result was used to derive the other wanted parameter, the ion flux. The derivation was done by calculating the photoelectron current mph at all time and subtracting the result from the total current. The retrieved difference gives the magnitude of the ion current for every measurement.

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27

Ugoletti, Margherita. "NIO1 negative ion beam investigation in view of ITER heating and current drive." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15796/.

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Negli ultimi decenni, la ricerca e lo sviluppo di nuove fonti di energia sono state oggetto di crescente interesse scientifico. In particolare, la fusione nucleare potrebbe essere la soluzione al problema energetico mondiale. ITER è attualmente il più grande esperimento di fusione nucleare in via di costruzione. Situato nel sud della Francia, sarà il più grande tokamak costruito al mondo con l'obiettivo di produrre 500 MW di potenza dai 50 MW di potenza fornitagli. Diversi metodi di riscaldamento del plasma sono in via di sviluppo per poter scaldare il core del plasma a temperature dell'ordine dei 15 keV. Tra questi, l'iniezione di fasci neutri è uno dei più importanti. Il progetto PRIMA, costituito dagli esperimenti SPIDER e MITICA in via di costruzione al Consorzio RFX a Padova, si pone come obiettivo lo studio dei futuri iniettori di fasci neutri di ITER. L'esperimento NIO1, anch'esso situato al Consorzio RFX, è una relativamente piccola sorgente a radio frequenza RF di ioni negativi, nato con l'obiettivo di caratterizzare la fisica delle sorgenti di ioni nell'ottica dei futuri utilizzi negli iniettori di fasci neutri, quali lo stesso MITICA. Questo lavoro di tesi, nato da una collaborazione tra i Laboratori Nazionali di Legnaro (LNL) e il Consorzio RFX, caratterizza il fascio di ioni negativi di NIO1. I dati raccolti durante le campagne sperimentali sono stati analizzati e confrontati, per testare le performance della nuova griglia di estrazione installata su NIO1 a maggio 2017. La caratterizzazione è stata fatta in diversi modi: confrontando qualitativamente i dati raccolti dalle varie diagnostiche; ricostruendo tomograficamente l'immagine dei 9 beamlets tramite i dati raccolti dalle telecamere; caratterizzando il plasma formatosi in seguito alla propagazione del fascio nel gas di fondo, tramite il confronto con i dati sperimentali e quelli ottenuti da una simulazione numerica Particles-In-Cell PIC.
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28

Seo, Geon S. "Time evolution of current and displacement of ion-exchange polymer/metal composite actuators." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280748.

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This dissertation describes the development of a coupled model for the analysis of a novel polymer/metal composite (IPMC) actuator under large external voltage. A general continuum model describing the transport and deformation processes of solid polymer electrolyte is proposed. The formulation is based on global integral postulates for the mass conservation, charge conservation, momentum equilibrium, the first law of thermodynamics, and the second law of thermodynamics. The global equations are localized in the volume and on the material surfaces bounding the polymer. The model is simplified to a three-component system comprised of a fixed negatively charged polymeric matrix, protons, and free water molecules within the polymer matrix. Among these species, water molecules are considered as the dominant specie responsible for the deformation of the IPMC actuators. In this work, the electrochemical process occurring at both electrodes is analyzed as boundary conditions during the deformation of actuator in the regime of large voltage (over 1.2 V). These are used in the framework of overpotential theory to develop boundary conditions for the water transport in the bulk of polymer. The proposed coupled model successfully captures the stress relaxation phenomenon due to water redistribution governed by diffusion. The fabrication process are described, and experiments including the role of initial water content on the electro-mechanical response of the actuator are also discussed. Comparison of simulations and experimental data showed good agreement.
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29

Joung, Sandra K. (Sandra Kyongmee). "Qualification of a medium current ion implantation system in a semiconductor production environment." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40220.

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30

Sjövall, Linus. "Robust adaptive control of current in test equipment for lithium ion battery systems." Thesis, KTH, Optimeringslära och systemteori, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141700.

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This thesis project have the purpose of investigating possibilities for a current control with respect to cell voltages in the testing procedures of large battery systems. The main goal is to design and implement a control that is not in need of considerable tuning, but still has stability and performance during all different conditions of testing. The dynamics of the battery system is largely dependant on the temperature, but other factors such as age also affect the behaviour, and most importantly the dynamics changes for different battery systems. Current control in a battery cell is relatively easy and with classic control theory methods one can achieve robustness with regards to stability, and this is largely used as a foundation for evaluating possibilities. To achieve good performance an adaptive control method is selected, where the changing gain of the system is one of the most important properties to determine. More specifically, a parameter based recursive least squares method is applied. Some special consideration is taken within designing the control to work in the digital networked system that constitutes the test rig with battery system, actuator and control. Generally, the significant properties of the cells in the battery system can be determined by the adaptation, and the performance is good considering the responsiveness of the subsystems surrounding the control. However, there are parts that may still be improved within the control by considering compensation for imperfections in the network and the treatment of data in closed systems.
Detta examensarbete har som syfte att undersöka möjligheterna till reglering av ström efter börvärde på cellspänningar i testning av stora batterisystem som är ämnade att användas i tunga hybridfordon. Det huvudsakliga målet är att utveckla och implementera en regulator som inte är i behov av större parametersättning men fortfarande behåller robusthet och prestanda vid olika typer av testning. En av de största faktorerna utöver byte av batterisystem är de förändringar som sker i celler vid olika temperaturer. Reglering av ström i battericeller är relativt enkelt och klassiska metoder för regulatordesign kan uppnå robusthet med avseende på stabilitet, och detta används till stor del för utvärdering av möjligheter till prestandaförbättring. För att uppnå snabb reglering används adaptiv reglerteknik där den varierande förstärkningen i systemet är viktigast at ta hänsyn till. Specifikt så används en parameterbaserad rekursiv metod där cellernas egenskaper bestäms under användning. Dessutom appliceras vissa kompensationer i form av tillståndsmaskiner för att få önskade egenskaper i det sammansatta systemet. De viktiga egenskaperna i cellerna bestäms med relativt hög precition utav de adaptiva algoritmerna och prestandaförbättringen mot tidigare använd reglering är stor. Dock är den slutgiltiga regulatordesignen inte optimal och vissa förbättringar kan fortfarande göras med avseende på kompensation for brister i mätenheter och behandling av data inom de inbyggda systemen.
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31

Cui, Qingzhou. "CURRENT OSCILLATIONS DURING COPPER ELECTRODISSOLUTION IN LITHIUM ION BATTERY AND ACIDIC CHLORIDE ELECTROLYTES." Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1162242616.

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32

Martins, Dália Teresa Al-Alavi. "Compact ion-source based on superionic rubidium silver iodide (RbAg4I5) solid electrolyte." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/11037.

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Dissertação para obtenção do Grau de Mestre em Engenharia Física
A compact ion-beam source based on rubidium silver iodide (RbAg4I5) solid electrolyte, deposited on a sharpened silver tip, has been developed and studied. Through an accelerating potential above 10 kV, established between emitter and collector, silver positive ions move through the electrolyte towards the emitting surface, where they are emitted from and accelerated. Via partial redox reaction occurring at the silver/RbAg4I5 interface, silver atoms are oxidised into Ag+ ions and migrate into the electrolyte, compensating the loss of emitted ions in the apex region. The emitted ions are collected by a Faraday cup, producing an electric current in the level of tens picoamperes. It was found that silver ions (atomic or clustered) make a major contribution to the measured ion current, although rubidium ions were also detected with concentration in six times lower than silver. The apex diameters of the final emitters were estimated in the range of 4-9 μm. The highest stable current was produced by an emitter whose apex diameter corresponds to 8.2 ± 0.5 μm. This current remained in the level of 20-25 pA for nearly 90 minutes and it was obtained at 92ºC, using an extraction voltage of 20 kV. Furthermore, it was observed that the current increased exponentially with temperature and linearly with applied voltage, at least for temperatures below 150 ºC and voltages in the range of 10-22 kV. Dependence on the apex diameter was not studied, since the RbAg4I5 film deposited on silver tips was not totally uniform. Several improvements should be performed to optimize the deposition methods, the design of heating system and methodology of the measurements (m/z characterization of the emitted particles). However, the developed ion-beam source can produce a stable current over a long period of time with minimal expenditure of energy and source material. Such sources have potential applications in materials science and spacecraft engineering as principal elements of miniaturized electric propulsion systems (ionic thrusters).
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Zakharov, Venjamin E., and Claudia-Veronika Meister. "Acceleration and heating in the auroral magnetosphere by current driven electrostatic ion cyclotron turbulence." Universität Potsdam, 2000. http://opus.kobv.de/ubp/volltexte/2007/1495/.

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A numerical MHD model is developed to investigate acceleration and heating of both thermal and auroral plasma. This is done for magnetospheric flux tubes in which intensive field aligned currents flow. To give each of these tubes, the empirical Tsyganenko model of the magnetospheric field is used. The parameters of the background plasma outside the flux tube as well as the strength of the electric field of magnetospheric convection are given. Performing the numerical calculations, the distributions of the plasma densities, velocities, temperatures, parallel electric field and current, and of the coefficients of thermal conductivity are obtained in a self-consistent way. It is found that EIC turbulence develops effectively in the thermal plasma. The parallel electric field develops under the action of the anomalous resistivity. This electric field accelerates both the thermal and the auroral plasma. The thermal turbulent plasma is also subjected to an intensive heating. The increase of the plasma of the Earth's ionosphere. Besides, studying the growth and dispersion properties of oblique ion cyclotron waves excited in a drifting magnetized plasma, it is shown that under non-stationary conditions such waves may reveal the properties of bursts of polarized transverse electromagnetic waves at frequencies near the patron gyrofrequency.
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34

McConnon, Jerome Sean. "Analysis of voltage and current signal processing in a Li-ion Battery Management System." Thesis, Monterey, California. Naval Postgraduate School, 2010. http://hdl.handle.net/10945/5185.

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Approved for public release; distribution is unlimited
d through a thorough signal analysis before and after each component. Specifically, the current signal is analyzed and the processes of a Hall Effect Sensor, an instrument amplifier, and an analog-to-digital converter are described. Additionally, the voltage signal and its processing by a voltage-to-frequency converter are analyzed and the FPGA programming is described. The accuracy of the collected data is shown and possible improvements to the system are documented.
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Molin, Johan. "Investigation of Correlations Between COV of Ion Integral and COV of IMEP in a Port-Injected Natural-Gas Engine." Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-15949.

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Correlations between the coefficient of variations (COV) of ion current integrals and COV of indicated mean effective pressure (IMEP) are investigated. The investigations are made to see if there is a possibility to use ion sense technique for closed loop combustion control to maximize Exhaust Gas Recirculation (EGR) level with remaining combustion stability. The engine studied in this thesis is a stoichiometric natural gas engine with a three way catalyst working with different EGR levels. One way to increase the efficiency in a stoichiometric natural gas engine is to maximize the EGR level [3]. With a higher EGR level it is possible to open the throttle even further with a result of lower pumping losses. Also temperature losses to chamber walls will be smaller with high EGR levels. A closed loop system controlling the EGR valve against COV of IMEP around 5 % is used for this engine. For COV of flame peak integral in range from 0 to 15-20% of COV of IMEP a linear correlation was found for lambda less than 1.3. For COV of two peaks integral a linear correlation was found for the entire measured range. This correlation may not be used for a robust EGR control system due to a small increase of COV of ion integral and due to a high variance in COV of ion integral. Correlations are discussed for different ion integrals with different air/fuels ratios and EGR levels. A control strategy is also presented.

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36

Rojko, Roman [Verfasser]. "New concepts for transverse beam stability in high-current heavy-ion synchrotrons / von Roman Rojko." Berlin : dissertation.de, 2003. http://d-nb.info/969655665/34.

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37

Patnaik, Somani. "An electrical network model for computing current distribution in a spirally wound lithium ion cell." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/85400.

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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2012.
"September 2012." Page 74 blank. Cataloged from PDF version of thesis.
Includes bibliographical references.
Lithium ion batteries are the most viable option for electric vehicles but they still have significant limitations. Safety of these batteries is one of the concerns that need to be addressed when they are used in mainstream vehicles, because of heating issues that may lead to thermal runaway. This work aims at supplementing the existing electrochemical heat distribution model of a spirally wound lithium ion battery with an electrical network that can model the heat losses due to electric resistances of the current collectors. The developed electrical network model is used to calculate the current and state-of-charge distribution throughout the spiral jelly roll, which can be used to determine electric heat losses. The results obtained from this model can then be used to optimize the shape and dimensions of the current collectors as well as the materials used in them.
by Somani Patnaik.
M. Eng.
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38

Sellars, Malcolm. "Electric field mill for the simultaneous measurement of electric field strength and ion current diensity." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/22039.

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In the last 20 years, the use of high voltage direct current (HVDC) power transmission has grown considerably. With the increase in the number of HVDC transmission lines and in the transmission voltages, concern has increased as to possible health effects. For research on these health effects to be carried out, it is necessary to measure the electrical environment ofHVDC transmission lines accurately. The electrical environment ofHVDC transmission lines is characterised by: Electric field strength E [Vim];Ion current density J [A/m²] ;Space charge density p [C/m³ ]. Typical values measured under HVDC transmission lines are: E = lOkV/m, J = 400nA/m² . This thesis describes the design, construction and testing of an electric field mill capable of measuring electric field strength from 0 to 25kV/m (resolution = lOV/m), and ion current density from 0 to 1000 nA/m² (resolution = 20nA/m² ). The electric field readings have an accuracy of ±8%. The ion current density readings have an accuracy of ±12%. The field mill was tested in the laboratory in a simulated HVDC environment, and found to give good performance. For operation under a HVDC line, the field mill design will need some alterations to make it weatherproof. The design considerations described in this thesis should be helpful in the design of electric field mills in general.
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39

Martí, Calatayud Manuel César. "STUDY OF THE TRANSPORT OF HEAVY METAL IONS THROUGH CATION-EXCHANGE MEMBRANES APPLIED TO THE TREATMENT OF INDUSTRIAL EFFLUENTS." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/46004.

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La presente Tesis Doctoral consiste en la determinación de las propiedades de transporte de diferentes especies catiónicas a través de membranas de intercambio catiónico. Las membranas de intercambio iónico son un componente clave de los reactores electroquímicos y de los sistemas de electrodiálisis, puesto que determinan el consumo energético y la eficiencia del proceso. La utilización de este tipo de membranas para el tratamiento de efluentes industriales no es muy extendida debido a los requisitos de elevada resistencia química y durabilidad que deben cumplir las membranas. Otro asunto importante radica en la eficiencia en el transporte de los iones que se quieren eliminar a través de la membrana. Normalmente, existe una competencia por el paso a través de las membranas entre diferentes especies debido al carácter multicomponente de los efluentes a tratar. Sin embargo, una mejora en las propiedades de las membranas de intercambio iónico permitiría la implantación del tratamiento mediante reactores electroquímicos de efluentes industriales con un contenido importante en compuestos metálicos, tales como los baños agotados de las industrias de cromado. La utilización de una tecnología limpia como la electrodiálisis conllevaría diferentes ventajas, entre las cuales destacan la recuperación de los efluentes para su reutilización en el proceso industrial, el ahorro en el consumo de agua y la disminución de la descarga de contaminantes al medio ambiente. La determinación de las condiciones de operación óptimas así como la mejora de las propiedades de transporte de las membranas constituye el principal tema de la presente investigación. Para ello, se emplearán diferentes tipos de membrana. En primer lugar, se estudiará el comportamiento de las membranas poliméricas comerciales que poseen unas propiedades de resistencia química elevadas, las cuales se tomarán como referencia. De forma paralela, se producirán membranas conductoras de iones a partir de materiales cerámicos económicos, ya que la resistencia de los materiales cerámicos a sustancias oxidantes y muy ácidas es mayor que la de los materiales poliméricos. Este punto constituye la parte más innovadora de la investigación, puesto que la mayoría de las membranas de intercambio iónico comerciales están basadas en materiales poliméricos que no pueden resistir las condiciones específicas de los efluentes industriales. Una vez determinadas las condiciones de operación óptimas, se realizarán ensayos en plantas piloto con el fin de confirmar los resultados obtenidos mediante las técnicas de caracterización y determinar el grado de recuperación y coste energético asociado a los procesos electrodialíticos de tratamiento de efluentes industriales.
Martí Calatayud, MC. (2014). STUDY OF THE TRANSPORT OF HEAVY METAL IONS THROUGH CATION-EXCHANGE MEMBRANES APPLIED TO THE TREATMENT OF INDUSTRIAL EFFLUENTS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/46004
TESIS
Premiado
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40

Oltean, Gabriel. "From Current Collectors to Electrodes : Aluminium Rod Structures for Three-dimensional Li-ion Micro-battery Applications." Doctoral thesis, Uppsala universitet, Institutionen för kemi - Ångström, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-215482.

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The potential use of 3D aluminium nanorod structures as current collectors and negative electrodes for 3D Li-ion micro-batteries was studied based on the use of relatively simple and cost-effective electrochemical and sol-gel deposition techniques. Aluminium rod structures were synthesised by galvanostatic electrodeposition using commercial porous membranes as templates. It was shown that the use of a short (i.e., 50 ms long) potential pulse (i.e., -0.9 V vs. Al3+/Al) applied prior to a pulsed current electrochemical deposition gave rise to homogeneous deposits with more even rod heights.  Electrophoretic and sol-gel deposition of TiO2 on the same substrates were also studied. The use of the sol-gel technique successfully resulted in a thin coating of amorphous TiO2 on the Al nanorod current collector, but with relatively small discharge capacities due to the amorphous character of the deposits. Electrophoretic deposition was, however, successful only on 2D substrates. Anodisation of titanium was used to prepare 3D TiO2 nanotube electrodes, with a nanotube length of 9 um and wall thickness of 50 nm. The electrodes displayed high and stable discharge capacities of 460 µAh/cm2 at a 0.1 C rate upon prolonged cycling with good rate capability. The 3D aluminium nanorod structures were tested as negative electrodes for Li-ion cells and the observed capacity fading was assigned to trapping of LiAl alloy inside the aluminium electrode caused by the diffusion of lithium into the electrode, rather than to pulverisation of the aluminium rods. The capacity fading effect could, however, be eliminated by decreasing the oxidation potential limit from 3.0 to 1.0 V vs. Li+/Li. A model for the alloying and dealloying of lithium with aluminium was also proposed. Finally, a proof-of-concept for a full 3D Li-ion micro-battery with electrodes of different geometries was demonstrated. The cell comprised a positive electrode, based on LiFePO4 deposited on a carbon foam current collector, with an area gain factor an order of magnitude larger than that for the Al nanorod negative electrode. This concept facilitates the balancing of 3D Li-ion cells as the positive electrode materials generally have significant lower specific energy densities than the negative electrodes.
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41

Ito, Hiroyuki. "High quality high current ion beam generation and transport systems including plasma-based space charge neutraliser." Thesis, University of Salford, 2003. http://usir.salford.ac.uk/42995/.

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This thesis discusses the development of an ion beam generation and transport system for the purpose of high current ion implantation and presents a method to achieve high quality beam generation and high transport efficiency. An advanced method of achieving ideal space charge neutralization of an ion beam as well as charge neutralization of implanted targets has also been developed and presented. This study was carried out in five main categories as described below. 1. Beam optics: The optical properties of the ion beam have to be well controlled through various beam transport devices. Beam transfer matrix calculation and Poisson's equation solver were used to determine beam optics. 2. Plasma generation: The ion beam is extracted from a plasma generated in the ion source. Therefore, the quality of ion beams depends largely on the characteristics of the source plasma. Plasma diagnostic tools were used to understand the desired plasma conditions. 3. Space charge neutralisation: Space charge neutralisation is essential to transport high perveance beams because a beam without neutralisation develops a high electric potential in itself that would scatter beam ions away. A plasma based charge neutraliser "Plasma Flood System" was developed to maintain space charge neutrality during implantation. 4. Low energy beam extraction and transport: Beam extraction and transport become difficult at lower energy due to growth of emittance and space charge. Beam divergence had to be minimized by tight optical control. 5. Microwave plasma sources as ultimate ion source: A microwave source was developed to obtain high current, ultra clean ion beams and long source life. The characteristics of microwave plasmas differ significantly from whose generated by other methods such as DC excitation. The source achieved the highest recorded beam currents for various species. All the technology and the methods described above were combined to develop a state-of-the-art high current ion implanter that has achieved world leading beam performance.
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42

Bartoš, Miroslav. "Pistolová páječka s napájením z baterií Li-Ion." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377105.

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This master‘s thesis deals with the design of battery powered soldering iron. The soldering iron will be placed in the plastic box from a conventional transformer soldering iron. First, we need to find the parameters of the original transformer soldering iron. Then design a synchronous step-down converter, driver of converter, BMS circuits, and component placement in a plastic box. The battery-powered soldering iron was successfully revived and tested, the final parameters of the converter are: voltage 0.4 V at 80 A current. The total power on the soldering wire is 32 W. Technically, this is a very interesting alternative to the classic version of the soldering iron, which can be used for assembly or repairs in poorly accessible locations.
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43

Hedin, Johan. "Ion cyclotron resonance heating in toroidal plasmas." Doctoral thesis, KTH, Alfvén Laboratory, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3073.

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44

Holub, Anna, and Jie Liu. "Recognizing Combustion Variability for Control of Gasoline Engine Exhaust Gas Recirculation using Information from the Ion Current." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-235.

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The ion current measured from the spark plug in a spark ignited combustion engine is used

as basis for analysis and control of the combustion variability caused by exhaust gas

recirculation. Methods for extraction of in-cylinder pressure information from the ion

current are analyzed in terms of reliability and processing efficiency. A model for the

recognition of combustion variability using this information is selected and tested on both

simulated and car data.

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45

Johnson, Gregory Howard 1965. "Features of a heavy-ion-generated-current filament used in modeling single-event burnout of power MOSFETs." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277796.

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Power MOSFETs are often required to operate in a space radiation environment; therefore, they are susceptible to a catastrophic failure mode called single-event burnout. Single-event burnout of power MOSFETs is initiated by the passage of an energetic-heavy ion through the parasitic BJT inherent to the power-MOSFET structure. The electron-hole pairs generated by the ion support a short-lived current source which imposes a base-emitter voltage on the parasitic BJT. If a sufficient base-emitter voltage is imposed, the parasitic BJT enters second breakdown and burnout of the MOSFET occurs. A semi-analytical model has been developed to predict the energy required of the incident ion to initiate burnout. This thesis addresses the portion of this model which relates the energy of the incident ion to the base-emitter voltage imposed on the parasitic BJT. The initial base-emitter potential is determined using image-source techniques.
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46

Lee, Jungpyo. "Theoretical study of ion toroidal rotation in the presence of lower hybrid current drive in a tokamak." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82866.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 175-182).
In this thesis, the effect of the lower hybrid current drive on ion toroidal rotation in a tokamak is investigated theoretically. Lower hybrid frequency waves are utilized to drive non-inductive current for steady state tokamaks and ion toroidal rotation is used to control disruptions and improve confinement. It has been observed in many tokamaks that lower hybrid waves can change the ion toroidal rotation. These measurements indicate that it may be possible to control rotation with lower hybrid waves, but to do it, it is necessary to understand the mechanisms underlying the rotation change. The toroidal angular momentum injected by the lower hybrid waves initiates acceleration in the the counter-current direction. The parallel and perpendicular components of the toroidal angular momentum are transferred from the waves to ions through electrons via two different channels, and the ions obtain the full toroidal angular momentum injected by the lower hybrid waves after several ion collision times. The momentum transferred to the ions is transported out by turbulent radial transport. The radial transport of toroidal angular momentum is evaluated using gyrokinetics corrected to the higher order in poloidal rhostar. The higher order corrections lead to momentum redistribution even in the absence of rotation, which is called intrinsic momentum transport. The intrinsic momentum transport due to diamagnetic effects is an important piece of the radial momentum transport. The change in the steady state rotation due to lower hybrid waves is estimated theoretically by evaluating the momentum source, the momentum pinch and diffusion, and the intrinsic momentum transport. The effect of the current profile on the intrinsic momentum transport, which is modified by the lower hybrid wave, may explain the reversal of the rotation change from counter-current direction to co-current direction observed in low plasma current discharges in Alcator C-Mod.
by Jungpyo Lee.
Ph.D.
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47

Lam, Andy Ka Ming. "Electrophysiological characterization of the human two-pore channel 2." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:3a16d16e-f692-40d7-87f7-920151896038.

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The Two-pore channel (TPC1-3) family represents a recently identified class of endolysosomal ion channels. TPCs were originally proposed to be promising candidate channels for NAADP-induced Ca2+ release. However, subsequent studies have emerged to propose an alternative view where TPCs may be Na+-selective channels regulated by the lysosome-specific phosphoinositide PI(3,5)P2 or voltage in an isoform-dependent manner. This thesis asks the question of whether pharmacological and ion permeation properties of TPCs, in particular the human TPC2, may satisfy or may be consistent with the requirement of a potential NAADP-sensitive Ca2+-release channel. These fundamental properties of hTPC2 were approached using patch-clamp electrophysiology and confocal fluorescence microscopy, and were analysed quantitatively to extract relevant physical parameters important to our understanding of their physiological and functional significance. Chapter 2 presents the basic electrophysiological characterisation of hTPC2. It follows a logical way by first determining the ion permeation properties, followed by the investigation of its physical relation with fractional Ca2+ current and Ca2+ nanodomains to rigorously prove that this Na+ selectivity is sufficient to ensure negligible Ca2+ leakage both experimentally and theoretically. This follows the logic that matter must not be created nor destroyed so that a Na+-selective channel that poses a physiologically significant energy barrier to Ca2+ permeation from one side would not lead to the creation of Ca2+ on the other side. Chapter 3 represents a natural progression from Chapter 2 and is aimed at investigating the underlying mechanisms responsible for the electrophysiological ion selectivity observed. This chapter also follows a logical way by first identifying spermine as a high valence intracellular blocker, its mutual antagonism with different external ionic species that allows the determination of ion-binding affinity, followed by the determination of the concentration dependence of ion conduction to identify possible lower affinity binding. By considering all the above qualities, the outcome is a coherent description and connection of ion binding selectivity, kinetic selectivity and ion binding configuration with the observed electrophysiological selectivity. Chapter 4 discusses the missing puzzles and how these questions might be addressed.
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48

Qin, Zhenpeng. "Modeling of Ion Transport for Micro/Nano Size Particles in Coulter Counter Application." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1240858653.

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49

Barapatre, Nirav. "Application of Ion Beam Methods in Biomedical Research." Doctoral thesis, Universitätsbibliothek Leipzig, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-126262.

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The methods of analysis with a focused ion beam, commonly termed as nuclear microscopy, include quantitative physical processes like PIXE and RBS. The element concentrations in a sample can be quantitatively mapped with a sub-micron spatial resolution and a sub-ppm sensitivity. Its fully quantitative and non-destructive nature makes it particularly suitable for analysing biological samples. The applications in biomedical research are manifold. The iron overload hypothesis in Parkinson\\\'s disease is investigated by a differential analysis of human substantia nigra. The trace element content is quantified in neuromelanin, in microglia cells, and in extraneuronal environment. A comparison of six Parkinsonian cases with six control cases revealed no significant elevation in iron level bound to neuromelanin. In fact, a decrease in the Fe/S ratio of Parkinsonian neuromelanin was measured, suggesting a modification in its iron binding properties. Drosophila melanogaster, or the fruit fly, is a widely used model organism in neurobiological experiments. The electrolyte elements are quantified in various organs associated with the olfactory signalling, namely the brain, the antenna and its sensilla hairs, the mouth parts, and the compound eye. The determination of spatially resolved element concentrations is useful in preparing the organ specific Ringer\\\'s solution, an artificial lymph that is used in disruptive neurobiological experiments. The role of trace elements in the progression of atherosclerosis is examined in a pilot study. A differential quantification of the element content in an induced murine atherosclerotic lesion reveals elevated S and Ca levels in the artery wall adjacent to the lesion and an increase in iron in the lesion. The 3D quantitative distribution of elements is reconstructed by means of stacking the 2D quantitative maps of consecutive sections of an artery. The feasibility of generating a quantitative elemental rodent brain atlas by Large Area Mapping is investigated by measuring at high beam currents. A whole coronal section of the rat brain was measured in segments in 14 h. Individual quantitative maps of the segments are pieced together to reconstruct a high-definition element distribution map of the whole section with a subcellular spatial resolution. The use of immunohistochemical staining enhanced with single elements helps in determining the cell specific element content. Its concurrent use with Large Area Mapping can give cellular element distribution maps.
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50

Mustacchi, Roberta. "The development of a bioreactor using ion exchange membranes and direct electric current for the separation of biotransformation products." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275248.

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