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Dissertations / Theses on the topic 'Pullet'

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Published: 10 December 2022

Last updated: 28 January 2023

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1

Magar, Vivek Dattatray. "Effect of juvenile dietary regime and time of beak trimming on pullet growth, subsequent egg production and incidence of prolapse in Leghorns." Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/53229.

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Beak trimming at two different ages, Week-1 and Week-8, under four dietary regimens, varying in percent crude protein (CP) and metabolizable energy (ME) were compared. The dietary regimens were conventional high energy (CHE), conventional medium energy (CME), conventional low energy (CLE) and step-up protein regimen (SUP). At 20 weeks of age, 192 birds from each beak-dietary treatment were housed in laying cages for 24 weeks of egg production. One-half of the birds were provided with high light intensity ranging from 20 to 70 lux and one-half with low intensity from 2.5 to 22 lux. Cumulative feed intake through 20 weeks of age for the CHE fed birds was significantly lower than that for the CLE fed birds but did not differ from that of the CME or the SUP fed birds. The feed intake of the CME and CLE groups did not differ from each other; however, both were significantly greater than that of the SUP fed birds. Birds reared on CME had the lowest protein consumption with no difference in protein consumption between CHE, CLE and SUP fed birds. Birds reared on the SUP regimen had the lowest ME intake followed by the CLE group with no significant difference between CHE and CME groups. By 20 weeks of age, there was no significant difference in body weight for CHE, CME and CLE birds with those on SUP being significantly lower than all other treatments. Livability for the 20-week growing phase did not differ among dietary treatments. The influence of age when beaks were trimmed (Week-1 or Week-8) on feed, protein, and energy intake, body weight or livability for the 20-week growing period did not differ between the two beak treatments. By 44 weeks of age, there were no significant body weight differences among any of the juvenile dietary treatments. Age at 50% production, hen-day and hen-housed egg production, egg weight, shell quality, feed per egg, livability and mortality due to prolapse per se did not differ significantly among juvenile dietary treatments for the six 28-day production period. Birds reared on SUP regimen laid a significantly higher number of pee-wee eggs (< 42.5 g) and a significantly lower number of extra-large eggs (63.8 - 70.8 g) than those fed the other diets. Age at beak trimming and level of light intensity did not influence any of the parameters evaluated during the laying period.
Master of Science

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2

CARLETO, NIVALDO. "Projeto, construção e caracterização de um modulador pulsado para a operação de uma válvula magnetron de potência." reponame:Repositório Institucional do IPEN, 2005. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11275.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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3

Cohen, Jacob Arthur. "Measuring the electric field of picosecond to nanosecond pulses with high spectral resolution and high temporal resolution." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37179.

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We demonstrate four experimentally simple methods for measuring very complex ultrashort light pulses. Although each method is comprised of only a few optical elements, they permit the measurement of extremely complex pulses with time-bandwidth products greater than 65,000. First, we demonstrate an extremely simple frequency-resolved-optical gating (GRENOUILLE) device for measuring the intensity and phase of pulses up to ~20ps in length. In order to achieve the required high spectral resolution and large temporal range, it uses a few-cm-thick second harmonic-generation crystal in the shape of a pentagon. This has the additional advantage of reducing the device's total number of components to three. Secondly, we introduce a variation of spectral interferometry (SI) using a virtually imaged phased array and grating spectrometer for measuring long complex ultrashort pulses up to 80 ps in length. Next, we introduce a SI technique for measuring the complete intensity and phase of relatively long and very complex ultrashort pulses. It involves making multiple measurements using SI (in its SEA TADPOLE variation) at numerous delays, measuring many temporal pulselets within the pulse, and concatenating the resulting pulselets. Its spectral resolution is the inverse delay range--many times higher than that of the spectrometer used. The waveforms were measured with ~ fs temporal resolution over a temporal range of ~ns and had time-bandwidth products exceeding 65,000, which to our knowledge is the largest time-bandwidth product ever measured with ~fs temporal resolution. Finally, we demonstrate a single-shot measurement technique that temporally interleaves hundreds of measurements with ~fs temporal resolution. It is another variation of SI for measuring the complete intensity and phase of relatively long and complex ultrashort pulses in a single shot. It uses a grating to introduce a transverse time delay into a reference pulse which gates the unknown pulse by interfering it at the image plane of an imaging spectrometer. It provided ~125 fs temporal resolution and a temporal range of 70 ps using a low-resolution spectrometer.

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4

Bordyugov, Grigory. "Dynamics and stability of pulses and pulse trains in excitable media." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=981984177.

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5

Fernández, González Alma. "Chirped pulse oscillators generating microjoule femtosecond pulses at megahertz repetition rate /." [S.l.] : [s.n.], 2007. http://edoc.ub.uni-muenchen.de/archive/00006967.

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6

Fernández, González Alma. "Chirped Pulse Oscillators: Generating microjoule femtosecond pulses at megahertz repetition rate." Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-69673.

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7

Bolatbek, Zhanibek. "Detection and Pulse Shaping of Continuous Wave and Pulsed Broadband Light." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1619634310138999.

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8

Somasundaram, Meena Sivalingam. "Pulsed power and load-pull measurements for microwave transistors." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003293.

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9

Chauhan, Vikrant Chauhan Kumar. "Pulse compression and dispersion control in ultrafast optics." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/37153.

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Pulse Compression and Dispersion Control in Ultrafast Optics Vikrant K. Chauhan 116 Pages Directed by Dr. Rick P. Trebino In this thesis, we introduced novel pulse compressors that are easy to align and which also compensate for higher order dispersion terms. They use a single dispersive element or a combination of dispersive elements in single-element-geometry. They solve the problem of extra-cavity pulse compression by providing control of the pulse width in almost all of the experiments performed using ultrashort pulses, and they even compensate for higher order dispersion. We performed full spatiotemporal characterization of these compressors and demonstrated their performance. We also developed a theoretical simulation of pulse compressors which is based on a matrix based formalism. It models the full spatiotemporal characteristics of any dispersion control system. We also introduced a simple equation, in its most general form, to relate the total dispersion and magnification introduced by an arbitrary sequence of dispersive devices. Pulse compressor characterization was done using interferometric measurements in the experiments presented in this work, but we also developed a method to measure pulses that uses polarization gating FROG for measuring two unknown pulses. In the last part, we briefly discuss the designing of a high energy chirped pulse amplification system.

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10

Bao, Ainan. "Ignition of hydrocarbon fuels by a repetitively pulsed nanosecond pulse duration plasma." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1198975288.

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11

Narsetti, Renuka. "Application of pulsed electric fields and magnetic pulse compressor technology in water disinfection." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/5842.

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Thesis (M.S.)--University of Missouri-Columbia, 2005.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (January 24. 2007) Includes bibliographical references.

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12

Grenier, Jason. "Design of a MOSFET-Based Pulsed Power Supply for Electroporation." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/844.

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The use of high-voltage pulsed electric fields in biotechnology and medicine has lead to new methods of cancer treatment, gene therapy, drug delivery, and non-thermal inactivation of microorganisms. Regardless of the application, the objective is to open pores in the cell membrane and hence either facilitate the delivery of foreign materials inside the cell or to kill the cell completely. Pulsed power supplies are needed for electroporation, which is the process of applying pulsed electric fields to biological cells to induce a temporary permeability in the cell membrane. The applications of pulsed electric fields are dependent on the output pulse shape and pulse parameters, both of which can be affected by the circuit parameters of the pulsed power supply and the conductivity of the media being treated.

In this research, two Metal Oxide Field Effect Transistor (MOSFET)-based pulsed power supplies that are used for electroporation experiments were designed and built. The first used up to three MOSFETs in parallel to deliver high voltage pulses to highly conductive loads. To produce pulses with higher voltages, a second pulsed power supply using two MOSFETs connected in series was designed and built. The parallel and series MOSFET-based pulsed power supplies are capable of producing controllable square pulses with widths of a few hundred nanoseconds to dc and amplitudes up to 1500 V and 3000 V, respectively. The load in this study is a 1-mm electroporation cuvette filled with a buffer solution that is varied in conductivity from 0. 7 mS/m to 1000 mS/m. The results indicate that by controlling the circuit parameters such as the number of parallel MOSFETs, gate resistance, energy storage capacitance, and the parameters of the MOSFET driver gating pulses, the output pulse parameters can be made almost independent of the load conductivity.

Using the pulsed power supplies designed in this work, an investigation into electroporation-mediated delivery of a plasmid DNA molecule into the pathogenic bacterium E. coli O157:H7, was conducted. It was concluded that increasing the electric field strength and pulse amplitude resulted in an increase in the number of transformants. However, increasing the number of pulses had the effect of reducing the number of transformants. In all of the experiments the number of cells that were inactivated by the exposure to the pulsed electric field was measured.

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13

Mukherjee, Anadi. "Two Photon Resonant Picosecond Pulse Propagation in Lithium Vapor." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc331546/.

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The work of this dissertation has been to prove that the coherence of multiphoton excitation can be studied by an appropriately phased and time delayed sequence of pulses. An application of this fundamental study of coherence has been made for the enhancement of third harmonic generation. The coherent recovery of the energy lost to the two photon absorption process enalled a larger propagation distance for the fundamental than in an interaction which is incoherent or coherent, but not using a 90 degree phase shifted pulse pair. Phase matching over this longer propagation distance gave an enhancement of third harmonic generation.

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14

Lee, Dongjoo. "Ultra-broadband phase-matching ultrashort-laser-pulse measurement techniques." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-07032007-113912/.

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Thesis (Ph. D.)--Physics, Georgia Institute of Technology, 2008.
First, Phillip, Committee Member ; Adibi, Ali, Committee Member ; Raman, Chandra, Committee Member ; Buck, John, Committee Member ; Trebino, Rick, Committee Chair.

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15

Wang, Ziyang. "Next Generation Ultrashort-Pulse Retrieval Algorithm for Frequency-Resolved Optical Gating: The Inclusion of Random (Noise) and Nonrandom (Spatio-Temporal Pulse Distortions) Error." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-04122005-224257/unrestricted/wang%5Fziyang%5F200505%5Fphd.pdf.

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Thesis (Ph. D.)--Physics, Georgia Institute of Technology, 2005.
You, Li, Committee Member ; Buck, John A., Committee Member ; Kvam, Paul, Committee Member ; Kennedy, Brian, Committee Member ; Trebino, Rick, Committee Chair. Vita. Includses bibliographical references.

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16

Kingsley-Shadish, Antonipillai. "Behaviour of Gammarus pulex (L.) (Crustacea, Amphipoda) in response to intermittent pulses of dissolved copper." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248015.

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17

Deutschmann-Olek, Andreas [Verfasser]. "Modeling and Control of Optical Pulse Amplifiers for Ultra-Short Laser Pulses / Andreas Deutschmann-Olek." Düren : Shaker, 2021. http://d-nb.info/1233547895/34.

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18

Shreenath, Aparna Prasad. "Measuring broadband, ultraweak, ultrashort pulses." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-07112005-171551/.

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Thesis (Ph. D.)--Physics, Georgia Institute of Technology, 2006.
Trebino, Rick, Committee Chair ; First, Phillip, Committee Member ; Ralph, Stephen, Committee Member ; Kennedy, Brian, Committee Member ; Buck, John, Committee Member.

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19

Braun, Michael [Verfasser], Steffen Johannes [Akademischer Betreuer] Glaser, and Kai-Olaf [Akademischer Betreuer] Hinrichsen. "Cooperative Pulses : towards global pulse sequence optimization / Michael Braun. Gutachter: Kai-Olaf Hinrichsen. Betreuer: Steffen Johannes Glaser." München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/101958792X/34.

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20

Qin, Yu. "Versatility of nonlinear optical phenomena induced by infrared pulses: application to pulse characterization, element analysis, and filamentation." Kyoto University, 2015. http://hdl.handle.net/2433/200464.

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21

Jang, Geon-Ho. "Design and implementation of pulse sequences for application in MRI /." free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9953868.

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22

Gungulo, Ana Lidia. "Expanding pulse production in Mozambique : identifying constraints and new strategies." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/41117.

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Pulses (common beans and cowpeas) provide a major alternative source of protein, and the rapid rise in food prices has led to an increase in the consumption of inexpensive pulses. The slow growth in pulse production has, however, led to a decline in availability. Thus, to overcome this decline in production, this study concern in expanding pulse production in Mozambique by using the agricultural research survey known as TIA. In addition, this study identified and analysed the critical drivers influencing production, as well as constraints and opportunities to expand pulse production in Mozambique. In studying the participation of smallholder farmers in pulse markets, the Heckman two-step approach was applied to avoid sample selection bias. In the first step a Probit model was estimated to capture the household’s decision of whether or not to participate in the market. The second step comprised of an OLS estimation to determine the significance of variables that contribute to the level of pulse sold. At national level, results indicate that the majority of households receive price information, but few households receive information on fertilizers and improved seed use. Most households also have poor access to credit and improved extension services, and low levels of membership of agricultural associations. A very small percentage of household farmers are engaged in pulse production, with male farmers more dedicated to the production of common beans and female farmers more dedicated to the production of cowpeas. In terms of market participation, the results reveal that female-headed households are less likely to participate in pulse markets. The critical factors that discourage entry into the pulse market are distance to the market and yield loss. The factors that give incentives to smallholders to participate in the pulse market are land size, price information and pulse price. The trade volume of common beans is relatively high and is affected by land size, pulse price and price information. In contrast, the trade volume of cowpeas is highly affected by bicycle ownership and ownership of livestock for animal traction. Cowpea prices also have a positive effect on the volume of cowpeas sold. Yield loss is a major factor that negatively affects the pulse trade, while land size has a negative effect on the volume of cowpeas sold. Land availability and price information provide good opportunities, in Mozambique, for expanding pulse production. The expansion of pulse production is however constrained by household access to public goods and services such as extension services, credit and membership to an agricultural association. Moreover, the expansion of pulse production in the country is also constrained by the absence of the use of productive technologies such as improved seed and fertilizer. Based on the results of the study, the recommendations are to expand extension services, improve access to improved technology, facilitate access to agricultural finance, and improve infrastructure and storage facilities. This would facilitate and give incentive to smallholder to expanding pulse production in Mozambique.
Dissertation (MSc Agric)--University of Pretoria, 2013.
gm2014
Agricultural Economics, Extension and Rural Development
unrestricted

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23

Galbraith, Martin Christopher Edward [Verfasser]. "Time-resolved spectroscopy with attosecond pulses and pulse trains: ultrafast relaxation in benzene cations / Martin Christopher Edward Galbraith." Berlin : Freie Universität Berlin, 2017. http://d-nb.info/1124465170/34.

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24

Baksh, Nicholas A. (Nicholas Anwar). "An autocorrelator-interferometer used to determine the pulse width of a pulsed laser used in two-photon endoscopy." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32882.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2005.
"May 2005."
Includes bibliographical references (leaf 9).
An autocorrelator-inferometer was designed to correctly assess the pulse width of pulse laser used in two photon endoscopy. The path length of the light was altered using a retro-reflecting corner cube attached to a 6880 galvanometer optical scanner controlled by a 671 series micro-max controller (both products by Cambridge Technologies Inc.) The scanner was selected due to its ability to traverse very small rotations with a constant angular velocity, thereby reducing any non-linearities (with respect to time) in the autocorrelation. The projected results of this autocorrelator suggest it can be used to analyze electromagnetic waves with pulses on the order of a couple picoseconds, however, due to an imbalance of the scanner's shaft, the device was broken before any tests could be performed. A preliminary analysis suggests that a circular shaft attachment could be used to prevent this problem in the future.
by Nicholas A. Baksh.
S.B.

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25

Tang, Suo [Verfasser], and Christoph H. [Akademischer Betreuer] Keitel. "Plasma High Harmonic Generation and Single Attosecond Pulse Emission from Ultraintense Laser Pulses / Suo Tang ; Betreuer: Christoph H. Keitel." Heidelberg : Universitätsbibliothek Heidelberg, 2018. http://d-nb.info/117725266X/34.

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26

Kornaszewski, Lukasz. "Novel sources of near- and mid-infrared femtosecond pulses for applications in gas sensing, pulse shaping and material processing." Thesis, Heriot-Watt University, 2008. http://hdl.handle.net/10399/2224.

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In this thesis the design, construction process and the performance of two femtosecond optical parametric oscillators and one second–harmonic generation femtosecond pulse shaper is described. One oscillator was applied to gas sensing while potential applications of other devices are outlined. ATi:sapphire oscillator was used to pump a periodically–poled lithium niobate– based optical parametric oscillator. This signal–resonant device was configured to produce broadband idler pulses tunable in the range of 2.7–3.4 μm. This wavelength coverage was matched to the ν3 optical absorption band of methane, and Fourier–transform spectroscopy of a CH4:N2 mixture was implemented by employing a mid–IR silica photonic bandgap fibre simultaneously as a gas cell and an optical waveguide. Methane sensing below a 1% concentration was demonstrated and the main limiting factors were identified and improvements suggested. Another optical parametric oscillator was demonstrated which was pumped by a commercial Yb:fibre master oscillator/power amplifier system and was based on a periodically–poled lithium niobate crystal. The signal was tunable between 1.42–1.57 μm and was intended as a source for a subsequent project for waveguide writing in silicon. The oscillator was a novel long–cavity device operating at 15 MHz. The 130 nJ pump pulse energies allowed for 21 nJ signal pulses at a pump power of 2 W. The performance of the oscillator was characterised via temporal and spectral measurements and the next steps of its development are outlined. Finally a pulse shaper based on second harmonic generation in a grating– engineered periodically–poled lithium niobate crystal was demonstrated. Pulses from a 1.53 μm femtosecond Er:fibre laser were compressed and then used as the input to the shaper. The performance of the shaper was tested by performing cross–correlation frequency–resolved optical gating measurements on the output second harmonic pulses and this confirmed the successful creation of multiple pulses and other tailored shapes including square and chirped pulses, agreeing well with theoretical calculations.

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27

Bowlan, Pamela. "Measuring the spatiotemporal electric." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28188.

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Thesis (M. S.)--Physics, Georgia Institute of Technology, 2009.
Committee Chair: Rick Trebino; Committee Member: Jennifer Curtis; Committee Member: John Buck; Committee Member: Mike Chapman; Committee Member: Stephen Ralph.

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28

Benwell, Andrew L. "Flashover prevention on polystyrene high voltage insulators in a vacuum." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5018.

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Thesis (M.S.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 18, 2008) Includes bibliographical references.

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29

Friedman, Melissa E. "Pulse shaping for broadband photoassociation of cold molecules." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:18d49cc2-9146-4ff8-b3b3-9e045bff039c.

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The development of the field of the science of ultra-cold matter has opened some exciting possibilities in exploring the quantum-mechanical processes which dominate matter interactions at the sub-microscopic scale. Although methods of cooling atoms are well established, molecular cooling is made difficult by molecules’ additional vibrational and rotational degrees of freedom. It was the goal of the research in this work to approach molecular cooling indirectly, by using broadband shaped-pulse photoassociation for the generation of tightly bound ultracold Rb₂ molecules. The experiments towards this goal conducted by our group included a pumpdecay experiment to observe the generation of ground state singlet or triplet molecules. However, attempts to observe an increase in ground state population have been unsuccessful. A pump-probe study of wavepacket dynamics in the 5s+5p electronic state was conducted in order to determine the appropriate timing for the application of an additional pulse to dump population into the ground state. Although the attempt to observe wavepacket oscillations has been unsuccessful, pump-probe studies have yielded the observation of loosely bound excited state molecules as a result of the photoassociation pulse. These results are promising as a first stage in a fully coherent pump-dump approach to stabilisation into the lowest vibrational ground state. This thesis will provide an introduction and overview to the concerns involved in addressing the problem of molecular cooling and generation. Experimental techniques will be discussed including pulsed laser systems, optical parametric amplifi- cation, and the presentation of an original design for pulse shaping with an acoustooptic modulator. The emphasis of these discussions will be on the principles and operating procedures required for the use of these devices as home-built systems. The thesis will conclude with the results of pump-probe experiments utilising the pulse shaper as a spectral cutting device.

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Gorodi, Suzie Mei. "Pulse, pulse, somersault." AUT University, 2009. http://hdl.handle.net/10292/1006.

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This project explores notions of seeing and knowing, underpinned by performative and phenomenological fields of enquiry that relate this exploration to the sensate experience of the viewer. A specific interest considers ideas of embodied vision with an aim at generating events that vacillate in the bodies of the audience. A primary focus is on the arena of encounter as a multi-sensory experiential event, and within this context this project proposes a temporal and spatial framework for exploration. Studio methods develop a cinematic-body of video work negotiating performative practice involving video projection and temporality. Pivotal goals are to explore the significance of the ‘chiasm’ between seeing and knowing, raising questions about how humans see, and how humans make how they see matter. Therefore, this thesis project progresses along experimental approaches to video installation, particularly in relation to the phenomena of encounter, the viewer, and film experience. The central motivation of this video practice is aimed at corporeal affect in the body/s of the audience. This thesis project is constituted as 80% practice-based work accompanied by a 20% exegesis.

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Kokorin, Denis [Verfasser], and Jürgen [Akademischer Betreuer] Hennig. "Magnetic resonance imaging with spatially-selective pulses using multiple transmission channels = Magnetresonanztomographie mit räumlich-selektiven HF-Pulsen unter Ausnutzung des parallelen Sendens." Freiburg : Universität, 2015. http://d-nb.info/1123482497/34.

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32

José, Eduardo Barqueros Muñoz. "Measurement of ultrashort laser pulses using the Second-Harmonic Generation Frequency-Resolved Optical-Gating : Characterization of an ultrashort laser pulse." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19369.

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Communication technologies are continuosly evolving since were invented the telegraph. Nowadays, one of the most interesting and relatively youngest field of telecommunications are the optical communications. The search of the shortest event ever created to measure very fast/short events is now possible because of the Light Amplification by Stimulated Emission of Radiation, longer known as laser.So well, we need to find the shortest event but we need to know how to measure it, since it is supposed that there is not a shorter event. So we need the pulse to measure itself, and its sound as we need to do a kind of autocorrelation.In order to measure a pulse, we need to get its intensity and phase in either the time or frequency domains. And, before the Frequency-Resolved Optical-Gating appearance, it was done with autocorrelation (time-domain) and spectrum (frequency-domain).

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Valset, Kjetil. "Vekst av BaSnO med Pulset Laser Deponering." Thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10391.

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I denne Masteroppgaven ble det dannet filmer av BaSnO på substrat av STO og Nb:STO. Filmene ble grodd i serier der parametrene som ble endret var laserfrekvens, lasereffekt(ved 2Hz og 10Hz)og temperaturen til substratet(ved 2Hz og 10Hz). Tykkelsen til de fleste filmene som ble deponert var mellom 200nm-350nm. For substrattemperaturer mellom 500°C-700°C ble det dannet filmer i hva som sannsynligvis er Ruddlesden Popper serien med en maksimal n kalkulert til å være 169 basert på satellittopper funnet i θ-2θ målinger. For filmer med substrattemperaturer i dette området ble det funnet en lineær sammenheng mellom deponeringsraten i Å per sekund og n i Ruddlesden Popper serien. Det ble funnet at den laveste temperaturen som en krystallinsk film kan bli dannet på minker når laserfrekvensen reduseres. Ved en laserfrekvens på 2Hz ble det dannet krystallinske filmer ned mot substrattemperaturer på 450°C. Ingen filmer ble forsøkt dannet under denne temperaturen og 450°C danner derfor ikke ingen nedre grense for vekst av krystallinske filmer av BaSnO. XPS målinger av filmene i laserfrekvensserien viser et fallende Ba/Sn forhold når høyden på lagene i filmene øker, i samsvar med hva man forventer i Ruddlesden Popper serien. Det ble også foretatt SIMS målinger av 3 filmer i laserfrekvensserien som avslørte at forholdet mellom Ba og Sn er stabilt igjennom hele filmen. SIMS målingene avslørte også Strontium forurensninger i ildematerialet og i filmene. For filmer med substrattemperaturer rundt 780°C ble satellittoppene svakere, muligens på grunn av en overgang fra 2D vekst til 3D vekst. Når laserenergien ved denne temperaturen ble senket ble det dannet filmer av hva som mest sannsynlig er 113 fasen til BaSnO. Det ble foretatt lekkasjestrømmålinger av en film i Ruddlesden Popper serien og lekkasjestrømmer på 1 A/ ble funnet. Det ble også foretatt annealing ved 400°C og 800°C på en av filmene. Dette reduserte intensiteten til satellittoppene i θ-2θ målingene litt da Ruddlesden Popper enhetscellene da går fra å stå ut av planet til å ligge i planet på filmen.

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34

Takayanagi, Jun, Norihiko Nishizawa, Hiroyuki Nagai, Makoto Yoshida, and Toshio Goto. "Generation of high-power femtosecond pulse and octave-spanning ultrabroad supercontinuum using all-fiber system." IEEE, 2005. http://hdl.handle.net/2237/6770.

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Fernelius, Mark H. "Effect of Full-Annular Pressure Pulses on Axial Turbine Performance." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3825.

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Pulse detonation engines show potential to increase the efficiency of conventional gas turbine engines if used in place of the steady combustor. However, since the interaction of pressure pulses with the turbine is not yet well understood, a rig was built to compare steady flow with pulsing flow. Compressed air is used in place of combustion gases and pressure pulses are created by rotating a ball valve with a motor. This work accomplishes two main objectives that are different from previous research in this area. First, steady flow through an axial turbine is compared with full annular pulsed flow closely coupled with the turbine. Second, the error in turbine efficiency is approximately half the error of previous research comparing steady and pulsed flow through an axial turbine. The data shows that a turbine driven by full annular pressure pulses has operation curves that are similar in shape to steady state operation curves, but with a decrease in turbine performance that is dependent on pulsing frequency. It is demonstrated that the turbine pressure ratio increases with pulsed flow through the turbine and that this increase is less for higher pulsing frequencies. For 10 Hz operation the turbine pressure ratio increases by 0.14, for 20 Hz it increases by 0.12, and for 40 Hz it increases by 0.06. It is demonstrated that the peak turbine efficiency is lower for pulsed flow when compared with steady flow. The difference between steady and pulsed flow peak efficiency is less severe at higher pulsing frequencies. For 40 Hz operation the turbine efficiency decreases by 5 efficiency points, for 20 Hz it decreases by 9 points, and for 10 Hz it decreases by 11 points. It is demonstrated that the specific power at a given pressure ratio for pulsed flow is lower than that of steady flow and that the decrease in specific power is lower for higher pulsing frequencies. On average, the difference in specific power between steady and pulsed flow is 0.43 kJ/kg for 40 Hz, 1.40 kJ/kg for 20 Hz, and 1.91 kJ/kg for 10 Hz.

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Rolong, Andrea. "Tissue Engineered Scaffolds and Three Dimensional Tumor Constructs to Evaluate Pulsed Electric Field Treatments." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/97320.

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This work investigates the use of irreversible electroporation (IRE) for tissue engineering applications and as a cancer ablation therapy. IRE uses short, high-intensity electric pulses to create pores in a cell's membrane and disrupt its stability. At a certain energy level, damage to the cell becomes too great and it leads to cell death. The particular mechanisms that drive this response are still not completely understood. Thus, further characterization of this behavior for cell death induced by pulsed electric fields (PEFs) will advance the understanding of these types of therapies and encourage their use to treat unresectable tumors that can benefit from the non-thermal mechanism of action which spares critical blood vessels and nerves in the surrounding area. We evaluate the response to PEFs by different cell types through experimental testing combined with computer simulations of these treatments. We show that IRE can be used to kill a specific type of bacteria that produce cellulose which can be used as an implantable material to repair damaged tissues. By killing these bacteria at particular times and locations during their cellulose production, we can create conduits in the overall structure of this material for the transport of oxygen and nutrients to the cells within the area after implantation. The use of tissue models also plays a key role in the investigation of various cancer treatments by providing a controlled environment which can mimic the state of cells within a tumor. We use tumor models comprised of a mix of collagen and cancer cells to evaluate their response to IRE based on the parameters that induce cell death and the time it takes for this process to occur. The treatment of prostate and pancreatic cancer cells with standard monopolar (only positive polarity) IRE pulses resulted in different time points for a full lesion (area of cell death) to develop for each cell type. These results indicate the presence of secondary processes within a cell that induce further cell death in the border of the lesion and cause the lesion to increase in size several hours after treatment. The use of high-frequency irreversible electroporation (H-FIRE)--comprised of short bursts of high-intensity, bipolar (both positive and negative polarity) pulses--can selectively treat cancer cells while keeping healthy cells in the neighboring areas alive. We show that H-FIRE pulses can target tumor-initiating cells (TICs) and late-stage, malignant cancer cells over non-malignant cells using a mouse ovarian cancer model representative of different stages of disease progression. To further explore the mechanisms that drive this difference in response to IRE and H-FIRE, we used more complex tumor models. Spheroids are a type of 3D cell culture model characterized by the aggregation of one or more types of cells within a single compact structure; when embedded in collagen gels, these provide cell-to-cell contact and cell-to-matrix adhesion by interactions of cells with the collagen fibers (closely mimicking the tumor microenvironment). The parameters for successful ablation with IRE and H-FIRE can be further optimized with the use of these models and the underlying mechanisms driving the response to PEFs at the cellular level can be revealed.
Ph. D.

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Kadja, Tchamie. "Chip Scale Tunable Nanosecond Pulsed Electric Field Generator for Electroporation." University of Dayton / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1556028923379642.

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Rondani, Bruno. "Projeto, desenvolvimento e construção de um modulador de pulso estado-solido para transmissores pulsados de alta potencia." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261786.

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Orientador: Jose Antenor Pomilio
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-06T14:09:31Z (GMT). No. of bitstreams: 1 Rondani_Bruno_M.pdf: 5870538 bytes, checksum: 69f2b2bd154400cd5b620b87a2c4fe8c (MD5) Previous issue date: 2005
Resumo: Descreve-se neste trabalho o desenvolvimento de uma topologia de modulador de pulso estado-sólido e a linha de retardo modular, para aplicação em transmissores pulsados de alta potência que utilizem válvulas de microondas magnetron empregadas comumente em radares de trajetografia, meteorologia e controle de tráfego aéreo. A pesquisa abrange o projeto, desenvolvimento e construção de um modulador de pulso destinado à modernização do transmissor do radar de trajetografia Bearn do Centro de Lançamentos de Foguetes da Barreira do Inferno, Natal -RN. O equipamento desenvolvido fornece pulsos de até 37,5kV e 60A em três modos de transmissão, a saber: monopulso longo, monopulso curto e bipulso. No modo monopulso longo, a largura de pulso é de 1,7µs e nos outros dois modos, 0,85µs. A taxa de repetição dos pulsos é de 585,5Hz. A unidade de modulação de pulso consiste de oito módulos de chaveamento em paralelo, conectados ao primário de um transformador de pulso de razão 1:50. Cada módulo contém dois trechos de linha de retardo e duas chaves estado-sólido e é capaz de gerar pulsos de até 790V e 390A nos diferentes modos de operação. A alimentação da linha de retardo é feita através de um circuito de carga composto por um indutor de alimentação e um circuito de Clipper. O indutor de alimentação faz com que a tensão de carga na linha seja dobrada em relação à tensão contínua presente na saída da fonte de alimentação de entrada, devido à ressonância série criada entre esse indutor e a capacitância total das linhas de retardo. O circuito de Clipper garante a regulação de tensão pulso a pulso e a proteção do modulador contra surto de sobre-corrente na carga e sobre-tensão nas linhas de retardo. Esta topologia foi desenvolvida para melhorar a confiabilidade e facilitar a manutenção dos transmissores de radar com a implementação do conceito de degradação suave (graceful degradation) do modulador de pulso
Abstract: This work describes the development of a modular line-type solid-state pulse modulator topology to be applied in magnetron pulsed power radar transmitters, commonly found on tracking, weather and air traffic management radars. This research includes the design, development and assembling of a pulsed modulator for the Barreira do Inferno Launching Center (CLBI, Natal-RN) Bearn tracking radar upgrade program. The equipment developed provides pulses of 37.5 KV and 60 A in three transmission modes: single long pulse, single short pulse and bipulse. In the single long pulse the pulse width is 1.7 µs and in the other modes 0.85 µs. The pulse repetition frequency is of 585.5Hz. The modulator unit is composed by eight switching modules connected in parallel with the primary windings of a 1:50 ratio pulse transformer. Each module has two pulse-forming network and two IGBT switches and it is capable of handling 790 V and 390 A in the three operational modes. An inductor and a Clipper circuit implement the pulse-forming network charging. The charging inductor allows charging the pulse-forming network with twice the supply voltage since there is a resonance with the total modulator capacitance. The Clipper circuit assures the pulse-to-pulse charging voltage regulation and protects the modulator against load over-current and over-voltage charging. This topology was developed to improve reliability and maintainability of radar transmitters by implementing the graceful degradation (soft failure mode) in the pulse modulator
Mestrado
Sistemas e Controle de Energia
Mestre em Engenharia Elétrica

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MACHADO, LEANDRO M. "Microusinagem de dielétricos com pulsos laser de femtossegundos." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10119.

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Made available in DSpace on 2014-10-09T12:34:59Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:04:28Z (GMT). No. of bitstreams: 0
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
FAPESP:08/00284-0

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40

Lindblom, Adam. "Inductive Pulse Generation." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6699.

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41

Lanz, B. (Brigitte). "Compact current pulse-pumped GaAs–AlGaAs laser diode structures for generating high peak-power (1–50 watt) picosecond-range single optical pulses." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526213569.

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Abstract Although gain-switching is a simple, well-established technique for obtaining ultrashort optical pulses generated with laser diodes, the optical energy in a pulse achievable from commercial structures using this technique is no more than moderate and the ‘spiking’ behaviour seen at turn-on is likely to evolve into trailing oscillations. This thesis investigates, develops and improves laser diodes in order to offer experimentally verified solutions for maximizing the optical energy so as to achieve a peak power of several watts in a single optical pulse of picosecond-range duration in the gain-switching operation regime, and for suppressing the energy located in any trailing pulses to a negligible level relative to the total optical pulse energy. This was addressed by means of either (i) an ultrashort pump current pulse with an amplitude range ~(1–10) A or (ii) custom laser diode structures, both options being capable of operating uncooled at room temperature (23±3°C). For the first solution a unique superfast gallium arsenide (GaAs) avalanche transistor was utilized as a switch in order to achieve an injection current pulse with a duration of < 1 ns, which is short enough to generate only a first optical ‘spike’ when pumping a commercial laser diode. The most promising structure with regard to the second solution was an edge-emitting semiconductor laser having a strongly asymmetric broadened double heterostructure with a relatively thick active layer. Laser pulses with full width at half maximum (FWHM) of ~100 ps and an optical energy of >3 nJ but with some trailing oscillations were achieved in experiments employing injection current pulses in the nanosecond range with an amplitude of ≤17 A, generated using inexpensive silicon (Si) electronics. The performance was improved by introducing a saturable absorber (SA) into the laser cavity, which suppressed the formation of trailing oscillations, resulting in a single optical pulse
Tiivistelmä ”Gain switching” (vahvistuskytkentä) on tunnettu tekniikka lyhyiden (<100 ps) optisten pulssien generoimiseen laserdiodeilla. Kaupallisia laserdiodirakenteita käyttäen optinen energia rajoittuu kuitenkin 10…100 pJ:n tasolle. Tällöinkin, erityisesti suurilla energiatasoilla, optisessa pulssissa ilmenee voimakkaita jälkioskillaatioita. Tässä väitöskirjassa tutkittiin ja kehitettiin kokeellisesti varmennettuja laserdiodilähetinrakenteita tavoitteena saavuttaa >1 nJ:n optisen pulssin energia ja ~100 ps:n pulssinpituus gain-switching -toimintamoodissa. Tavoitteena oli myös minimoida jälkipulssien energia. Tutkimuksen pääsisältönä on kaksi toimintaperiaatetta: Toisessa tekniikassa päähuomio kohdistuu laseridiodin virta-ajuriin, johon kehitettiin elektroniikka, joka kykenee tuottamaan nopeita virtapulsseja laajalla pulssivirta-alueella. Virtapulssin nopeuden kasvattamisen (<1 ns) osoitettiin edistävän gain switching -ilmiötä. Toisena tekniikkana tutkittiin räätälöityä laserdiodirakennetta, joka sisäisen toimintansa perusteella tuottaa dynaamisessa ohjaustilanteessa tehokkaan ja nopean laserpulssin. Kummankin periaatteen osoitettiin toimivan huonelämpötilassa (23±3°C) ilman erillistä jäähdytystä. Ensimmäisessä ratkaisussa käytettiin nopeaa gallium-arsenidi (GaAs) -avalanchetransistoria virtakytkimenä, jolla saavutettiin <1 ns FWHM injektiovirtapulssi 10 A:n virtatasolla. Tällainen virtapulssi on riittävän lyhyt virittämään ”gain switching” -ilmiön nJ-energiatasolla. Lupaavin rakenne toiseksi ratkaisuksi oli reunaemittoiva puolijohdelaseri, jossa epäsymmetrinen aaltoputki ja aktiivinen alue ovat sijoitettu normaalista laserdiodirakenteesta poiketen rinnakkain. Tällä rakenteella voitiin tuottaa ~100 ps levyisiä (FWHM) ja >3 nJ optisen kokonaisenergian omavia laserpulsseja edullisella pii-pohjaisella (Si) elektroniikalla luoduilla 1.5–2 ns:n (FWHM) ≤17 A injektiovirtapulsseilla. Suorituskykyä saatiin edelleen parannettua istuttamalla saturoiva absorbaattori (SA) laserin optiseen onteloon. Tämän osoitettiin vähentävän jälkioskillaatioiden muodostumista

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42

Bendixsen, Luis Sebastian Caballero. "The design and construction of a compact, high-current pulsed power generator based on multiple low impedance pulse forming lines and networks." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526548.

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43

Piggott, Alfred J. III. "Transient thermoelectric supercooling| Isosceles current pulses from a response surface perspective and the performance effects of pulse cooling a heat generating mass." Thesis, Michigan Technological University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10004791.

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With increased public interest in protecting the environment, scientists and engineers aim to improve energy conversion efficiency. Thermoelectrics offer many advantages as thermal management technology. When compared to vapor compression refrigeration, above approximately 200 to 600 watts, cost in dollars per watt as well as COP are not advantageous for thermoelectrics. The goal of this work was to determine if optimized pulse supercooling operation could improve cooling capacity or efficiency of a thermoelectric device. The basis of this research is a thermal-electrical analogy based modeling study using SPICE. Two models were developed. The first model, a standalone thermocouple with no attached mass to be cooled. The second, a system that includes a module attached to a heat generating mass. With the thermocouple study, a new approach of generating response surfaces with characteristic parameters was applied. The current pulse height and pulse on-time was identified for maximizing Net Transient Advantage, a newly defined metric. The corresponding pulse height and pulse on-time was utilized for the system model. Along with the traditional steady state starting current of I_max, I_opt was employed. The pulse shape was an isosceles triangle. For the system model, metrics new to pulse cooling were Q_c, power consumption and COP. The effects of optimized current pulses were studied by changing system variables. Further studies explored time spacing between pulses and temperature distribution in the thermoelement. It was found net Q_c over an entire pulse event can be improved over I_max steady operation but not over steady I_opt operation. Q_c can be improved over I_opt operation but only during the early part of the pulse event. COP is reduced in transient pulse operation due to the different time constants of Q_c and P_in. In some cases lower performance interface materials allow more Q_c and better COP during transient operation than higher performance interface materials. Important future work might look at developing innovative ways of biasing Joule heat to T_h.

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44

Lauvmo, Stig. "Syntese av komplekse oksider med pulset laser deponering." Thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10301.

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Norges første pulset laser deponerings (PLD) lab ble påbegynt høsten 2005 av NTNU i samarbeid med Sintef og ble ferdigstilt våren 2006. Pulset laser deponering brukes til deponering av komplekse oksider som SrRuO3(SRO) og BaTiO3(BTO), deponeringsmetoden til PLD er en fysikalsk fordampnings deponering. Metoden fungerer ved at pulset laserstråle slår løs targetmateriale som deponeres som en tynnfilm på et nærliggende substrat. PLD laben består av en laser, to deponeringskammere, Sintef og NTNU kontrollerer hvert sitt, optikk for styring av laserstrålen og måleutstyr som strålingstermometer og wattmeter. For å kontrollere PLD parametrene som brukes under deponering brukes det et PC program. All kommunikasjon mellom PC og kammer gjøres gjennom en hylle på RS484 protokollen. Programvare, hylle og kammer er levert av Twente Solid State Technology (TSST). Bestemmelse av vekstparameter for tynnfilmer av henholdsvis SRO og BTO ble gjennomført i begge kammerene. Karakterisering ble gjennomført på alle tynnfilmene ved hjelp av røntgendiffraksjon (XRD) og atomærkraft mikroskopi (AFM). Antall atomlag(N), avstanden mellom atomlagene(c) og full bredde halv maksimum (FWHM) verdien ble funnet ved hjelp av XRD. Ved hjelp av AFM ble kvaliteten til overflaten observert og stegstørrelsen ble bestemt. Ideell veksttemperatur i Sintef kammeret ble funnet ved at SRO tynnfilmer ble grodd ved 5 forskjellige temperaturer 600, 650, 700, 750 og 800 °C. Ut fra resultatene til denne serien ble det bestemt at tynnfilmen grodd ved en temperatur på 700 °C ga best kvalitet. Ved denne temperaturen ble en jevn terrassestruktur observert med en steghøyde på 0,356 nm. Resistansen ble målt til 76 Ω over 2 mm av tynnfilmen, resistans målningene ble foretatt ved hjelp av et multimeter. Vekstparametrene til BTO ble bestemt i NTNU kammeret. Temperaturen ble satt til 700 °C mens laserenergien og oksygentrykket ble forandret. Laserenergien måtte bli redusert med 2 halvbølgeledere for å få effekten lav slik at tynnfilmene ikke ble for tykke, laserenergien ble redusert til 0,18 W. Filmer grodd ved en laserenergi på 0,18 W og trykk på 5∙E-3 mbar produserte tynnfilmer med en jevn overflate. FWHM av BTO filmene varierte mellom 0,02° og 0,03°, som indikerte tynnfilmer av god krystallinks orden.

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45

Grepstad, Jon Olav. "Tynnfilmepitaksi ved pulset laserdeponering av SrRuO3 : En vekstparameterstudie." Thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10392.

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Tynnfilmepitaksi ved pulset laserdeponering av SrRuO3 på TiO2-terminert (001)-orientert SrTiO3-substrat, er i dette arbeidet undersøkt over et stort spekter av deponeringssystemets vekstparametere. Veksten er overvåket ved in situ målinger med elektronstrålediffraksjon (RHEED). Det er vist at tilnærmet perfekt epitaksi er mulig i flere begrensede områder i parameterrommet, der reproduserbarhet hovedsakelig er begrenset av parameterne trykk og temperatur. Resultatene antyder at dette har sammenheng med at kravet til nøyaktig reprodusering av ablasjonsforhold vil variere avhengig av hvor, i spekteret av trykk og temperatur, veksten foregår. Arbeidet omfatter også en undersøkelse av instrumentering. Optimalisering av temperaturmålinger med pyrometer, limeprosedyre og innstilling av laserenergitetthet på target er gjort. Resultater fra denne undersøkelsen viser at deponeringstemperaturen er reproduserbar med ±13 °C og at laserenergi-tettheten på target er usikker. En rekke tiltak som kan minimere usikkerheten i laserenergitettheten er gjennomgått.

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Burgess, A. D. "Food restriction, growth and carcass composition of pullets." Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376399.

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47

Kong, Lingyuan. "Coupled belt-pulley mechanics in serpentine belt drives." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1069789616.

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48

Arena, Christopher Brian. "Advancements in Irreversible Electroporation for the Treatment of Cancer." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/50605.

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Irreversible electroporation has recently emerged as an effective focal ablation technique. When performed clinically, the procedure involves placing electrodes into, or around, a target tissue and applying a series of short, but intense, pulsed electric fields. Oftentimes, patient specific treatment plans are employed to guide procedures by merging medical imaging with algorithms for determining the electric field distribution in the tissue. The electric field dictates treatment outcomes by increasing a cell's transmembrane potential to levels where it becomes energetically favorable for the membrane to shift to a state of enhanced permeability. If the membrane remains permeabilized long enough to disrupt homeostasis, cells eventually die. By utilizing this phenomenon, irreversible electroporation has had success in killing cancer cells and treating localized tumors. Additionally, if the pulse parameters are chosen to limit Joule heating, irreversible electroporation can be performed safely on surgically inoperable tumors located next to major blood vessels and nerves. As with all technologies, there is room for improvement. One drawback associated with therapeutic irreversible electroporation is that patients must be temporarily paralyzed and maintained under general anesthesia to prevent intense muscle contractions occurring in response to pulsing. The muscle contractions may be painful and can dislodge the electrodes. To overcome this limitation, we have developed a system capable of achieving non-thermal irreversible electroporation without causing muscle contractions. This progress is the main focus of this dissertation. We describe the theoretical basis for how this new system utilizes alterations in pulse polarity and duration to induce electroporation with little associated excitation of muscle and nerves. Additionally, the system is shown to have the theoretical potential to improve lesion predictability, especially in regions containing multiple tissue types. We perform experiments on three-dimensional in vitro tumor constructs and in vivo on healthy rat brain tissue and implanted tumors in mice. The tumor constructs offer a new way to rapidly characterize the cellular response and optimize pulse parameters, and the tests conducted on live tissue confirm the ability of this new ablation system to be used without general anesthesia and a neuromuscular blockade. Situations can arise in which it is challenging to design an electroporation protocol that simultaneously covers the targeted tissue with a sufficient electric field and avoids unwanted thermal effects. For instance, thermal damage can occur unintentionally if the applied voltage or number of pulses are raised to ablate a large volume in a single treatment. Additionally, the new system for inducing ablation without muscle contractions actually requires an elevated electric field. To ensure that these procedures can continue to be performed safely next to major blood vessels and nerves, we have developed new electrode devices that absorb heat out of the tissue during treatment. These devices incorporate phase change materials that, in the past, have been reserved for industrial applications. We describe an experimentally validated numerical model of tissue electroporation with phase change electrodes that illustrates their ability to reduce the probability for thermal damage. Additionally, a parametric study is conducted on various electrode properties to narrow in on the ideal design.
Ph. D.

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Ivey, Jill Winters. "Investigating the Applications of Electroporation Therapy for Targeted Treatment of Glioblastoma Multiforme Based on Malignant Properties of Cells." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78806.

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Glioblastoma multiforme (GBM) is the most common and lethal primary brain cancer with an average survival time of 15 months. GBM is considered incurable with even the most aggressive multimodal therapies and is characterized by near universal recurrence. Irreversible electroporation (IRE) is a cellular ablation method currently being investigated as a therapy for a variety of cancers. Application of IRE involves insertion of electrodes into tissue to deliver pulsed electric fields (PEFs), which destabilize the cell membrane past the point of recovery, thereby inducing cell death. While this treatment modality has numerous advantages, the lack of selectivity for malignant cells limits its application in the brain where damage to healthy tissue is especially deleterious. In this dissertation we hypothesize that a form of IRE therapy, high-frequency IRE (H-FIRE), may be able to act as a selective targeted therapy for GBM due to its ability to create an electric field inside a cell to interact with altered inner organelles. Through a comprehensive investigation involving experimental testing combined with numerical modeling, we have attained results in strong support of this hypothesis. Using tissue engineered hydrogels as our platform for therapy testing, we demonstrate selective ablation of GBM cells. We develop mathematical models that predict the majority of the electric field produced by H-FIRE pulses reach the inside of the cell. We demonstrate that the increased nuclear to cytoplasm ratio (NCR) of malignant GBM cells compared to healthy brain—evidenced in vivo and in in vitro tissue mimics—is correlated with greater ablation volumes and thus lower electric field thresholds for cell death when treated with H-FIRE. We enhance the selectivity achieved with H-FIRE using a molecularly targeted drug that induces an increase in NCR. We tune the treatment pulse parameters to increase selective malignant cell killing. Finally, we demonstrate the ability of H-FIRE to ablate therapy-resistant GBM cells which are a focus of many next-generation GBM therapies. We believe the evidence presented in this dissertation represents the beginning stages in the development of H-FIRE as a selective therapy to be used for treatment of human brain cancer.
Ph. D.

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Antelmann, Olivia. "Erkennung und Charakterisierung gefährlicher selbstzersetzlicher Substanzen." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963194291.

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