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Safety and Techno-Economic Analysis of Solvent Selection for Supercritical Fischer-Tropsch Synthesis ReactorsHamad, Natalie 2011 December 1900 (has links)
Fisher-Tropsch Synthesis is a primary pathway for gas-to-liquid technology. In order to overcome commercial problems associated with reaction and transport phenomena, the use of supercritical solvents has been proposed to increase chemical conversion and improve temperature control. One of the major challenges in designing the supercritical FTS systems is the solvent selection. Numerous alternatives exist and should be screened based on relevant criteria. The main aim of the thesis was to develop a safety metric that can be incorporated in the selection of an optimal supercritical solvent or a mixture of solvents. The objective was to minimize the cost while satisfying safety constraints or to establish tradeoffs between cost and safety. Hydrocarbons from C3 to C9 were identified as feasible solvents for FTS purposes. The choice of these solvents is dependent on their mixture critical temperature and pressure requirements that need to be satisfied upon entry into the FTS reactor. A safety metric system was developed in order to compare the risk issues associated with using the aforementioned solvents. In addition, an economic analysis of using the different solvents was performed. Finally, a case study was solved to illustrate the use of the proposed metrics and the selection of solvents based on safety and techno-economic criteria.
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The Subminiature Flight Safety SystemWoodard, Tracy, Dehmelt, Chris 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / Weapons platform testing and monitoring have historically consisted of custom telemetry and flight safety system solutions tailored to the requirements (including Title 10 Mandates) and size constraints of individual platforms. The size of these individual components of these systems has necessitated that warhead replacement to facilitate insertion of these units to support test and evaluation activities. Currently there are no products available to meet these requirements in a miniaturized and modular package. L-3 Communications Telemetry East (L-3 TE) has developed an extensive background in providing solutions to gather vital missile and target information over the last several decades. Under the auspices of Eglin AFB, L-3 TE is leading a multi-disciplinary team to design and develop the Subminiature Flight Safety System (SFSS) to support existing and new weapons applications. SFSS is a universal, small, and low cost redundant flight termination system (FTS) that incorporates encoding, processing and TSPI capacities that provides critical health/safety/welfare monitoring and allows for highly efficient telemetering of all weapon application and FTS data. The SFSS is intended as a solution to allow weapon system developers, test agencies, and range safety officers the ability to track, monitor, and if necessary, terminate all types of weapon systems. It is designed to interface with newly developed weapon systems, while providing backward compatibility to meet existing requirements with minimal modifications to the weapon. The SFSS components are intended to significantly reduce the cost and improve the quality of test support by providing a highly integrated solution that minimizes physical intrusion into weapon systems, by eliminating the need for warhead removal. In addition, a common hardware platform will reduce overall system cost of acquisition and maintenance to the government, a key element in today's world of stressed budgets.
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Doktrin för luftoperationer : ett dokument i takt med tiden eller ännu en hyllvärmare? / The Swedish Doctrine for Air Operations : a document in pace with the present or yet another drug on the marketNordin, Jan-Olov January 2009 (has links)
<p><em>Doktrin för luftoperationer</em> fastställdes som styrande dokument för alla luftoperationer 2005. Har då doktrinen blivit det styrande dokument i Flygvapnet som den är tänkt att vara?</p><p>I denna uppsats avser jag undersöka till vilken grad <em>Doktrin för luftoperationer</em> är implementerad i flygvapnets ledning och om doktrinen används som styrande dokument i utformningen av ordrar, direktiv och TOEM.</p><p>Jag har genom en kvalitativ textanalys granskat två centrala dokument ur olika perspektiv, för att utröna <em>till vilken grad</em> doktrinen används som styrande dokument. Jag har även intervjuat utvalda delar i flygvapnets ledning för att få ledningens uppfattningar av graden av implementering. Jag har i uppsatsen använt mig av en tregradig skala: <em>Inte alls</em>, <em>Till del</em> samt <em>Fullständigt</em> implementerad.</p><p>Genom dessa analyser har jag kunnat dra slutsatsen att <em>Doktrin för luftoperationer</em> endast <em>till del</em> är implementerad i flygvapnets ledning.</p> / <p>The Swedish doctrine for air operations was released and became effective in 2005. The doctrine was supposed to be a ruling document but is that the fact?</p><p>The aim of this study is to investigate at what level the doctrine has been implemented in the leadership of the Swedish Air Force and if the doctrine is in use as a ruling document when writing orders, directive and tactical, organisational, economical objectives (TOEM) for the sub-units.</p><p>The scientific method of this investigation is a qualitative text analysis where I analysed two vital documents in order to measure the level of implementation. For that purpose I have used a three grade scale: <em>not</em> implemented, <em>partly</em> and finally <em>fully</em> implemented.</p><p>The conclusion I draw after examining the subject is that the Swedish doctrine for air operations is only <em>partly</em> implemented in the Air Force.</p>
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Doktrin för luftoperationer : ett dokument i takt med tiden eller ännu en hyllvärmare? / The Swedish Doctrine for Air Operations : a document in pace with the present or yet another drug on the marketNordin, Jan-Olov January 2009 (has links)
Doktrin för luftoperationer fastställdes som styrande dokument för alla luftoperationer 2005. Har då doktrinen blivit det styrande dokument i Flygvapnet som den är tänkt att vara? I denna uppsats avser jag undersöka till vilken grad Doktrin för luftoperationer är implementerad i flygvapnets ledning och om doktrinen används som styrande dokument i utformningen av ordrar, direktiv och TOEM. Jag har genom en kvalitativ textanalys granskat två centrala dokument ur olika perspektiv, för att utröna till vilken grad doktrinen används som styrande dokument. Jag har även intervjuat utvalda delar i flygvapnets ledning för att få ledningens uppfattningar av graden av implementering. Jag har i uppsatsen använt mig av en tregradig skala: Inte alls, Till del samt Fullständigt implementerad. Genom dessa analyser har jag kunnat dra slutsatsen att Doktrin för luftoperationer endast till del är implementerad i flygvapnets ledning. / The Swedish doctrine for air operations was released and became effective in 2005. The doctrine was supposed to be a ruling document but is that the fact? The aim of this study is to investigate at what level the doctrine has been implemented in the leadership of the Swedish Air Force and if the doctrine is in use as a ruling document when writing orders, directive and tactical, organisational, economical objectives (TOEM) for the sub-units. The scientific method of this investigation is a qualitative text analysis where I analysed two vital documents in order to measure the level of implementation. For that purpose I have used a three grade scale: not implemented, partly and finally fully implemented. The conclusion I draw after examining the subject is that the Swedish doctrine for air operations is only partly implemented in the Air Force.
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Molecular-Size Selective Zeolite Membrane Encapsulated Novel Catalysts for Enhanced Biomass to Liquid (BTL) ProcessesCimenler, Ummuhan 03 April 2017 (has links)
80% of energy usage in the word comes from fossil fuels (coal, oil, natural gas) and among the fossil fuels, oil is the most consumed energy source especially in transportation. However, due to concerns about energy demand and energy sustainability, global warming and dependency on foreign oil, generation of renewable fuels is crucial for transportation. Biomass to Liquid (BTL) is a promising process available to produce renewable liquid fuels. BTL fuels have great potential to meet the growing demand for liquid fuels, mitigating climate change, and providing value to rural areas. However, there are two major challenges with biofuels produced from BTL. One of the major challenge is the H2:CO ratio of biomass gasification product is insufficient for production of hydrocarbon fuels due to formation of methane and tars. The steam reforming of hydrocarbons, to improve the H2:CO ratio, is generally conducted as part of the gas conditioning. However, tars cause the catalysts to deactivate rapidly. Secondly, for fuels produced from the gasification route regardless of feedstock source, there is an economy-of-scale issue. Therefore, it is desirable to seek ways of process intensification to allow small scale plants to be more economical. Zeolites can be used to solve these challenges since they have reactant selectivity property.
To achieve a catalyst capable of reforming methane without potential for deactivation by tars, the encapsulation of a core reforming catalyst with porous zeolite shell is examined in this dissertation. After detailed introduction in the first chapter, a composite H-β zeolite membrane encapsulated 1.6wt%Ni/1.2wt%Mg/Ce0.6Zr0.4O2 steam reforming catalyst was prepared by a physical coating method in the second chapter of the study. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analyses indicated that H-β zeolite was coated successfully on the core reforming catalyst. The pore size of H-β zeolite shell was between 0.43 and 0.57 nm, as measured by the HK method. Steam reforming of CH4 and C7H8 (as a tar model) were conducted with the composite H-β zeolite coated reforming catalyst, the two components individually, and physical mixtures of the two components as a function of temperature (780–840°C). CH4 conversion was enhanced by a factor of 2–3 (depending on temperature) for the composite catalyst as compared to the core reforming catalyst individually even though the zeolite did not have any activity alone. Possible reasons for the enhanced CH4 conversion include confined reaction effects (increase residence time within pores) of the catalyst containing the zeolite coating and/or Al3+ promotion of the active sites. Alternatively, due to molecular-size selectivity, the composite H-β zeolite coated reforming catalyst demonstrated a decrease in C7H8 conversion when compared to the uncoated reforming catalyst. The results validate the use of size selective catalysts to control molecular traffic and enhance the reforming reactant selectivity.
A composite catalyst consisting of an outer layer of zeolite membrane encapsulating an inner reforming catalyst core was synthesized by a double physical coating method to investigate reactant selectivity (ratio of methane/toluene conversion rate) in steam reforming of methane (CH4) and toluene (C7H8). A double encapsulation (51 wt % H-β zeolite) of a 1.6 wt % Ni−1.2 wt % Mg/Ce0.6Zr0.4O2 steam reforming catalyst was compared to a singly coated composite catalyst (34.3 wt % H-β zeolite) to investigate zeolite thickness effects on the conversion of different sized hydrocarbons. The increase in the zeolite content from 34.3 to 51 wt % decreased both CH4 and C7H8 conversions (by up to 14% depending upon the temperature) as a result of the increase in diffusional limitations. Weisz−Prater criteria and Thiele moduli calculations confirmed that the reactions were performed under internal diffusion limitations. The C7H8 conversion of the 51 wt % composite (SR@β51%) catalyst was similar to the zeolite alone, indicating negligible contribution from the protected catalyst core. The reactant selectivity increased by up to 1.5 times on SR@β51% in comparison to the SR@β34.3% composite. Combined reforming at 800 °C on the SR@β51% catalyst indicated that the catalyst was stable during the 10 h time on stream.
Continuing this work, a non-acidic Silicalite-1 zeolite membrane encapsulated 1.6wt%Ni-1.2wt%Mg/Ce0.6Zr0.4O2 steam reforming composite catalyst, synthesized by a physical coating method, was used to investigate effect of encapsulation on size selective steam reforming, using methane (CH4) and toluene (C7H8) as representative species. Weisz-Prater Criteria and Thiele moduli calculations indicated internal diffusion limitations. Combined reforming of CH4 and C7H8 at 800°C on the composite catalyst demonstrated stability during the 10 h time on stream while uncoated SR catalyst deactivated. The non-acidic Silicalite-1 encapsulated catalyst showed decreases (~2-7%) in both CH4 and C7H8 conversions compared to acidic H-β zeolite confirming that shell acidity did contribute to conversion and suggesting that shell defects/grain boundaries were responsible for the C7H8 conversion.
Finally, low temperature 0.16wt%Pt–1.34wt%Ni–1.00wt%Mg/(Ce0.6Zr0.4)O2 reforming catalyst was triple coated with H-β zeolite (60 wt% of zeolite) to be utilized synthesis of combination steam reforming catalyst (SR) and Fischer-Tropsch Synthesis (FTS) catalyst (CRAFT) for a single-step conversion of methane to liquid fuels. Scanning electron microscopy (SEM) image and energy-dispersive spectroscopy (EDS) analysis result demonstrated that H-β zeolite was successfully encapsulated onto the low temperature reforming catalyst. The catalyst was tested in steam reforming of methane (CH4) and toluene (C7H8) and the results was compared with 51 wt%. While CH4 conversions are very similar on the 60wt% composite catalyst with 51wt% composite catalyst, no C7H8 conversion was seen on the 60 wt% composite catalyst. Thus, it is concluded that the 60 wt% composite catalyst can be utilized to synthesis CRAFT catalyst.
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Enraizamento adventício de estacas de Sebastiania schottiana Müll. Arg. / Adventitious rooting of cuttings of Sebastiania schottiana Müll. Arg.Frassetto, Eduardo Garcia 19 June 2007 (has links)
The aim of this work was to verify the cuttings rooting potential of Sebastiana schottiana as mechanism of vegetative propagation. Cuttings were collected next to the edges of Soturno River, Faxinal de Soturno County, situated in the regions of Plateaus and central depression
of the Rio Grande Do Sul State, Brazil. Plants donors of cuttings were 5 years of age old approximately. In the work were subdivided in of 4 tests. In experiment 1, cuttings were cut and classified in accordance with the position in apex, medium and basal portions, with 30 cm of length. Monthly collections of the material by a period of 12 months were made, being the cuttings placed in containers with water and 15 cm of cutting submerged. The percentage of rooting, number and length of roots, number and length of shoots were evaluated after 60 days. In experiment 2, basal, medium and apex cuttings collected in the month of September of 2005 were absorbed in solution of Orgasol®FTS in the dosages of 0; 5; 10 and 15 mL.L-1 during 1 minute and submerged 15 cm of cutting, in containers with sand of medium granulation. The rooting percentage, dry weight of roots and shoots, length and diameter of longer root were evaluated after 75 days. In experiment 3, collected basal and medium cuttings in the month of April of 2006 were absorbed in solution of 15 mL.L-1 Orgasol® FTS during 0, 15, 30 and 45 minutes and placed in plastic bags to a depth of 15 cm, having sand of medium granulation. The rooting percentage, dry weight of roots and shoots, number of longer and smaller root than 3 cm of length, length and diameter of the longer root were evaluated after 150 days. In experiment 4, two tests were carried out: (a) Cuttings removed from shoots with 15 cm of length were classified in basal or apical position. Cuttings were immerged in IBA solution (0, 1, 2, 4 and 8 mg.L-1) for 1 minute and placed in Plantmax® for
60 days in a Greenhouse. The rooting percentage, dry weight of roots and shoots, number of roots and shoots and the length of roots and shoots were evaluated, (b) Basal cuttings were disinfested and immersed during 24 hours in IBA soluction (0; 0.1; 1; 2; 4 and 8 mg.L-1) and placed in glass bottles with solution of ¼ of WPM medium for a period of 30 days in climatized room. In experiment 1, the basal cuttings (88%), medium (56%) and apex (25%) collected in the May month presented better rooting. The basal cuttings had showed greater number and length of roots and shoots during the 12 months of evaluation. In experiment 2, the dosage of 5 mL.L-1 did not stimulate the rooting, whereas the dosages of 10 and 15 mL.L- 1 caused an increase in the rooting of 18% until reaching in the dosage of 15 mL.L-1, 28%. All
tested dosages, basal cuttings (26.25%) presented greater rooting than medium (20,83) and the apex (18.33%). In experiment 3, the increase of immersion time of the cuttings in solution of 15 mL.L-1 Orgasol®FTS, stimulated an increment in the rooting at basal cuttings of 25% for
36% and in the medium cuttings of 29% for 46%, as well as in the dry weight of roots and shoots and in the number of roots longer than 3 cm. In the experiment 4A, the basal cuttings presented greater rooting in the concentration of 4 mg.L-1 IBA (20.83%) and the apex cuttings in the 2 mg.L-1 IBA (12.35%). In the experiment 4B the better rooting of cuttings was in solution of 8 mg.L-1 IBA (18.75%). Transversal and longitudinal cuts of the rooting cuttings removed from shoots in experiment 4 were done. The adventitious roots of the cuttings originated to the xilematic vases, arround to pericycle cels. / No presente trabalho estudou-se o potencial de enraizamento de estacas de S. schottiana como mecanismo de reprodução vegetativa. O material vegetal foi coletado em matrizes
com aproximadamente 5 anos de idade, às margens do Rio Soturno, no município de Faxinal do Soturno, situado nas regiões fisiográficas do Planalto e Depressão Central do Rio
Grande do Sul. O estudo se constitui de 4 experimentos: no primeiro (1), estacas classificadas de acordo com a posição no ramo em apicais, medianas e basais, com 30 cm
de comprimento foram coletadas mensalmente por um período de 12 meses, e colocadas em recipientes com água, com a metade da estaca submersa. Aos 60 dias foram avaliadas
a porcentagem de enraizamento, número e comprimento de raízes e das brotações. No experimento 2, estacas das três posições no ramo coletadas no mês de setembro de 2005
foram embebidas em solução de Orgasol®FTS nas dosagens de 0, 5, 10 e 15 ml.L-1 durante 1 minuto e enterradas na profundidade de 15 cm, em recipientes com areia de granulação média como substrato. Avaliou-se aos 75 dias, a porcentagem de enraizamento; massa seca de raízes e brotações; comprimento e diâmetro da raíz mais longa. No experimento 3, estacas basais e medianas coletadas no mês de abril de 2006 foram embebidas em solução de 15 ml.L-1 de Orgasol® FTS, durante 0, 15, 30 e 45 minutos e colocadas em sacos plásticos a uma profundidade de 15 cm, em areia de granulação média e, avaliadas após 150 dias, considerando a porcentagem de enraizamento; massa seca de raízes e brotações; número de raízes maiores e menores que 3 cm de comprimento; comprimento e diâmetro da raiz mais longa. No experimento 4 foram realizados dois testes: (A) estacas obtidas de brotações do ano, foram seccionadas em 15 cm de comprimento e classificadas de acordo com a posição em basais e apicais. Posteriormente foram imersas em solução de AIB (0, 1, 2, 4 e 8 mg.L-1) durante 1 minuto e colocadas em tubetes com substrato Plantmax® onde permaneceram por 60 dias em casa de vegetação. Avaliou-se a porcentagem de
enraizamento, massa seca de raízes e brotações, número de raízes e brotações, comprimento de raízes e brotações; em (B) estacas basais foram desinfestadas e imersas durante 24 horas em solução de AIB (0, 0,1, 1, 2, 4 e 8 mg. L-1) e cultivadas em frascos com solução de ¼ de WPM por um período de 30 dias em sala climatizada. Avaliou-se os
mesmos parâmetros do testes anteriores e ainda foram feitos cortes transversais e longitudinais das estacas enraizadas no experimento 4, onde se usou a técnica do paraplasto-resina . Os resultados do experimento 1, demonstram que as estacas basais (88%), medianas (56%) e apicais (25%) coletadas no mês de maio apresentaram o melhor
enraizamento. As estacas basais apresentaram maior número e comprimento de raízes e brotações durante os 12 meses de avaliação. No experimento 2, a dosagem de 5 ml.L-1 não
estimulou o enraizamento, enquanto que as dosagens de 10 e 15 ml.L-1 causaram um aumento na porcentagem de enraizamento de 18% até atingir na dosagem de 15 ml.L-1,
28%. Em todas as dosagens testadas, as estacas basais (26,25%) apresentaram maior enraizamento que as medianas (20,83) e apicais (18,33%). No experimento 3, o aumento do
tempo de embebição das estacas em solução de Orgasol®FTS a 15 ml.L-1, estimulou um incremento na porcentagem de enraizamento em estacas basais de 25% para 36% e das
nas estacas medianas de 29% para 46%. Proporcionou um aumento da massa seca das de raízes e brotações e, no número de raízes maiores que 3 cm. No experimento 4 (A) as
estacas basais apresentaram maior porcentagem de enraizamento na concentração de 4 mg.L-1 de AIB (20,83%) e as estacas apicais na concentração de 2 mg.L-1 de AIB (12,35%). No experimento 4 (B) a maior porcentagem de enraizamento das estacas foi na concentração de 8 mg.L-1 de AIB (18,75%). Os cortes anatômicos indicam que as raízes
adventícias das estacas caulinares surgem próximas aos vasos xilemáticos, provavelmente do periciclo.
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Development of a Subminiature Enhanced Flight Termination ReceiverWoodard, Tracy, Vetter, Jeff, Rodzinak, Jason 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / As the size of missiles and UAVs shrink, so does the volume available for the Flight Termination System (FTS). Small, light weight FTS systems open up applications not possible with the larger and heavier conventional FTS systems. This paper presents a novel approach for the design, implementation and test of a subminiature Flight Terminate System Receiver for use in the Subminiature Flight Safety System (SFSS). This receiver implements the new digital-based Enhanced Flight Termination System (EFTS) protocol, while maintaining a volume of less than 1 cubic inch with power consumption of less than 2 watts. Combining all of the necessary functionality into a small package while meeting the rigorous requirements of the Range Commanders Council (RCC) specifications (EMI, vibration and shock) presented significant challenges. The Subminiature Enhanced Flight Termination Receiver used in the SFSS has been named the "SEFTR".
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Etude structurale de PBP3 et localisation des six « Penicillin-Binding Proteins » de Streptococcus pneumoniae : implication dans la croissance et la division bactérienne.Morlot, Cecile 17 November 2003 (has links) (PDF)
L'objectif de ma thèse était de réaliser une étude de la synthèse de la paroi de Streptococcus pneumoniae, paroi qui participe à la croissance et la division bactérienne et fait intervenir les « Penicillin-Binding Proteins » (PBPs). J'ai étudié la localisation du répertoire complet des six PBPs au cours du cycle cellulaire de S. pneumoniae, ce qui a révélé des similitudes inattendues entre les mécanismes de division des bactéries de type bacille et coque. J'ai déterminé le rôle spécifique de chaque PBP dans la synthèse de la paroi et mis en valeur la contribution de PBP3, une D,D-carboxypeptidase, dans la régulation de la division bactérienne. J'ai par ailleurs déterminé la structure tridimensionnelle de PBP3 à 2.8 Å de résolution, ce qui m'a permis de contraindre les modèles de synthèse de la paroi chez le pneumocoque.
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Countering Aging Effects through Field Gate SizingHenrichson, Trenton D. 14 January 2010 (has links)
Transistor aging through negative bias temperature instability (NBTI) has become a major lifetime constraint in VLSI circuits. We propose a technique that uses
antifuses to widen PMOS transistors later in a circuit?s life cycle to combat aging. Using HSPICE and 70nm BPTM process numbers, we simulated the technique on four circuits (a ring oscillator, a fan-out four circuit, an ISCAS c432 and c2670). Over the lifetime of the circuit, our simulations predict a 8.89% and a 13% improvement in power in the c432 and c2670 circuits respectively when compared to similarly performing traditional circuits.
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Studium nestabilních částic a prekurzorů biomolekul pomocí spektroskopických technik / The Study of Transient Species and Precursors of Biomolecules using Spectroscopic TechniquesFerus, Martin January 2012 (has links)
The presented thesis is focused on a spectroscopic study of unstable radicals, ions and molecules in a positive column glow discharge and laser plasma. The research of these fragments is supplemented by a study of biomolecules formation from these species and influence of catalysts. Molecular dynamics of radicals, ions and unstable molecules has been studied using a time resolved Fourier transform infrared spectroscopy. Time resolved spectra of CH4, HCONH2, BrCN, CH3CN, CF3Br, (CF3)2CHBr positive column glow discharges have been measured and simulated using a kinetic model including molecular dynamics, collisions and chemical and radiation transfer processes. The model has been compared with our experimental results and time resolved spectra were described in details. Fit to a complex reaction mechanism has been used to estimate a rate constant of a HCN conversion to HNC by a collision with H radical. The study of precursors of biomolecules was focused on chemical consequences of a laser induced dielectric breakdown in formamide vapor and gaseous carbon monooxide with 18 O labeled water. Dissociation products have been detected using the Fourier transform absorption spectroscopy. The experimental results have been explained by a help of a chemical laser spark dynamics model. Additionally, our the...
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