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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Nuclear masses of A=184 and A=188 isobars via Q-beta measurement

Campeau, Norbert Gilles Joseph. January 1985 (has links)
No description available.
12

A New Mass Measurement for Galaxy Clusters Using Position and Radial Velocity

Fultz, Kayla Jo January 2010 (has links)
No description available.
13

A cooler Penning trap to cool highly charged radioactive ions and mass measurement of 24Al

Chowdhury, Usman 30 June 2016 (has links)
Penning trap mass spectrometry (PTMS) can be used to test the Standard Model (SM) and to answer the questions related to the origin and abundance of the elements in the universe. There are several facilities worldwide specialized in PTMS and some of them can measure the masses of isotopes with half-lives in the range of milliseconds. TRIUMF’s ion trap for atomic and nuclear science (TITAN) is one such facility. In mass measurement the precision is linearly proportional to the charge state of the ion of interest. To increase the charge state, ions are charge-bred using an electron beam ion trap (EBIT) at TITAN. However, the charge breeding process introduces an energy spread among the ions which adversely affects the precision of the mass measurement. To overcome this problem a cooler Penning trap (CPET) was designed, assembled and is now being tested off-line. This thesis presents the first systematic test results of CPET. We also present the result of the first Penning trap mass measurement of the isotope 24Al, which is five times more precise than the previous atomic mass evaluation (AME2012) value. The precise and accurate mass of 24Al is important for both astrophysics and for test of the standard model (SM). The resonance energy (E_r) calculated for the 23Mg(p,gamma)24Al reaction using the ground state mass of 24Al reported in this thesis shows a 2s deviation from the direct measurement. On the other hand, tests of the SM by evaluating f_t values using isospin T = 1 nuclides have reached a high precision level. Effort is now shifting towards the T = 2 nuclides, which are far from stability compared to their T = 1 counterparts. For this reason, the ground state masses of T = 2 nuclides and of their decay products are required to be known with high precision. 24Al is the daughter of one such nucleus, 24Si. The ground state mass of 24Al reported in this thesis will be useful to test the SM. / October 2016
14

Ein Vergleich zwischen der digitalisierten Filmradiographie und der digitalen Lumineszenzradiographie als Verfahren zur Verlaufskontrolle der Distraktionsosteogenese

Khan, Martin 30 June 2003 (has links)
Das Ziel dieser Studie war die Evaluierung zweier radiologischer Methoden zur Belastbarkeitsvorhersage des Regenerates bei einem Verfahren zur Kallusdistration. Im Rahmen einer tierexperimentellen Großtierstudie (Tiermodell Yucatan-Schweine) wurden die DLR und die DFR als Röntgenverfahren zur Dokumentation des zeitlichen Verlaufs der Regeneratkonsolidierung verwendet. Nach Tötung der Tiere erfolgte der Vergleich zwischen den radiologischen Daten und den biomechanisch gemessenen Werten der untersuchten Tibiae (Festigkeit, Steifigkeit). Das Knochengewicht wurde mittels einer Eichkurve in Aluminiumäquivalent EAT umgerechnet. Anhand der EAT-Werte der einzelnen Versuchstage konnte ein Zuwachs an Knochenfestigkeit festgestellt werden. Die Festigkeit des Knochenregenerates wurde nach der Tötung der Tiere biomechanisch bestimmt und daraufhin mit den EAT-Werten des letzten Versuchtages korreliert. Die digitalisierte Filmradiographie zeigte eine Korrelation des EAT-Wertes am letzten Versuchstag mit der torsionalen Steifigkeitsmessung von r=0,71 und mit dem maximalen Drehmoment von r=0,69. Die DLR konnte demgegenüber eine Korrelation des EAT-Wertes der Distraktionszone mit der torsionalen Steifigkeit von r=0,89 ebenso wie mit dem maximalen Drehmoment von r=0,8 nachweisen. Demzufolge ist eine zuverlässige Verlaufsbeurteilung des Knochenregenerates mit der hier eingeführten Dichtemessung möglich. Beide Verfahren sind geeignet, quantitative Aussagen über die Belastbarkeit des Kallusgewebes bei der Distraktionsosteogenese im Tiermodell zu machen. Die Meßungenauigkeit der Methode war vernachlässigbar, die Meßergebnisse waren unabhängig vom Untersucher. Trotz der hohen Genauigkeit dieser Methode im Tiermodell kann noch keine Aussage über die Anwendung der Verfahrens beim Menschen gemacht werden. Daher werden weitere Studien notwendig sein, um hierüber Klarheit zu schaffen. / The aim of the study was an evaluation of two radiologic methods to predict the strength of bone regeneration in distraction osteogenesis. In this animal study the digitized radiography and the digital luminescence radiography were used for the documentation of bone regeneration. After the death of the animals a comparision between radiologic data and biomechanical data of the tibia was performed. The bone mass was determined by a calibration curve in equivalent aluminium thickness (EAT). On the basis of the EAT data of each examination day an increase of the bone strength could be determined. The bone strength was assessed after the sacrification by biomechanical testing and correlated with the radiologic data of the last examination day. The digitized radiography showed a correlation with the torsional stiffness of r=0,71 and with the maximal torsional moment of r=0,69. The digital luminescence radiography showed a correlation with the torsional stiffness of r=0,89 and with the maximal torsional moment of r=0,8. Therefore a reliable bone mass measurement is available by this method. Both radiographic procedures are suitable to predict the strength of bone regeneration in distraction osteogenesis in this experimental animal study. The inaccuracy of the method was negligible and independent to the investigator. But for all that high accuracy of the method a statement concerning the applicability of this method in humans in not possible. Therefore further investigation are neccessary.
15

Liquid Chromatography-Mass Spectrometry as a Tool for Drug Metabolite Identification in Biological Fluids : With Application to Ketobemidone

Sundström, Ingela January 2007 (has links)
<p>Electrospray ionization (ESI) mass spectrometry (MS) in combination with liquid chromatography (LC) is an excellent tool for the identification of drug metabolites. Utilizing this hyphenated technique in combination with proper sample pretreatment, the metabolic pathways of the analgesic drug ketobemidone were investigated in human urine and rat microdialysate from blood and brain. Two novel phase I metabolites (ketobemidone N-oxide and meta-hydroxymethoxyketobemidone) and three novel phase II metabolites (glucuronic acid conjugates of ketobemidone, norketobemidone and hydroxymethoxyketobemidone) were identified in human urine. Further, norketobemidone and ketobemidone N-oxide were identified in rat microdialysate from brain after regional distribution of ketobemidone in striatum. This indicates that the brain itself has the possibility to metabolize ketobemidone. </p><p>Synthetic ketobemidone metabolites were used for comparison of retention times and tandem MS spectra with the possible metabolites recovered from the biological samples. The conjugated metabolites were identified by accurate mass measurements and tandem MS spectra of the aglycones. The accuracy of the estimated masses was better than 2.1 ppm for two out of three conjugates in presence of internal standard.</p><p>On-line micro-SPE was successfully used for trapping and desalting of the microdialysates. The small SPE pre-column made it possible to inject approximately 100 times more sample on the analytical column compared to injection without pre-column. Selective trapping was demonstrated for the polar catechol amine metabolite, dihydroxyketobemidone, which forms covalent complexes with phenylboronic acid (PBA). A fluorinated silica type stationary phase was the only column out of several tested that was able to separate ketobemidone and all relevant phase I metabolites. </p><p>Liquid chromatography and mass spectrometry are independently valuable tools in the field of analytical pharmaceutical chemistry. The present study showed that the combination of LC-MS, with its excellent selectivity and sensitivity, offers an outstanding tool in the qualitative analysis of drugs and metabolites in biological fluids. </p>
16

Liquid Chromatography-Mass Spectrometry as a Tool for Drug Metabolite Identification in Biological Fluids : With Application to Ketobemidone

Sundström, Ingela January 2007 (has links)
Electrospray ionization (ESI) mass spectrometry (MS) in combination with liquid chromatography (LC) is an excellent tool for the identification of drug metabolites. Utilizing this hyphenated technique in combination with proper sample pretreatment, the metabolic pathways of the analgesic drug ketobemidone were investigated in human urine and rat microdialysate from blood and brain. Two novel phase I metabolites (ketobemidone N-oxide and meta-hydroxymethoxyketobemidone) and three novel phase II metabolites (glucuronic acid conjugates of ketobemidone, norketobemidone and hydroxymethoxyketobemidone) were identified in human urine. Further, norketobemidone and ketobemidone N-oxide were identified in rat microdialysate from brain after regional distribution of ketobemidone in striatum. This indicates that the brain itself has the possibility to metabolize ketobemidone. Synthetic ketobemidone metabolites were used for comparison of retention times and tandem MS spectra with the possible metabolites recovered from the biological samples. The conjugated metabolites were identified by accurate mass measurements and tandem MS spectra of the aglycones. The accuracy of the estimated masses was better than 2.1 ppm for two out of three conjugates in presence of internal standard. On-line micro-SPE was successfully used for trapping and desalting of the microdialysates. The small SPE pre-column made it possible to inject approximately 100 times more sample on the analytical column compared to injection without pre-column. Selective trapping was demonstrated for the polar catechol amine metabolite, dihydroxyketobemidone, which forms covalent complexes with phenylboronic acid (PBA). A fluorinated silica type stationary phase was the only column out of several tested that was able to separate ketobemidone and all relevant phase I metabolites. Liquid chromatography and mass spectrometry are independently valuable tools in the field of analytical pharmaceutical chemistry. The present study showed that the combination of LC-MS, with its excellent selectivity and sensitivity, offers an outstanding tool in the qualitative analysis of drugs and metabolites in biological fluids.
17

Etude de la production de paires de quarks TOP avec ATLAS au LHC, mesure de la masse du quark TOP / Study of the production of top quark pairs with the ATLAS detector at the LHC, measurement of the top quark mass

Cinca, Diane 22 September 2011 (has links)
Découvert en 1995 à Fermilab, le quark top est le dernier quark découvert. La mesure de ses propriétés permet de tester les prédictions du Modèle Standard et de contraindre la masse du boson de Higgs. De par ses propriétés, le quark top est aussi un partenaire privilégié dans la recherche de particules de Nouvelle Physique attendues à l'échelle du TeV. Ce travail de thèse, effectué auprès du détecteur ATLAS au LHC, présente les méthodes mises en oeuvre afin de mesurer la masse du quark top dans sa désintégration semileptonique. Différentes méthodes de reconstruction des évènements top sont présentées ainsi qu'une analyse dédiée basée sur les arbres de décision boostés. Ses performances sont quantifiées. La mesure précise de la masse du quark top nécessite une compréhension approfondie de l'échelle en énergie des jets. Deux stratégies sont présentées afin de calibrer les jets légers et les jets issus de quark b à l'échelle partonique. Les performances d'un ajustement cinématique appliqué à la mesure de la masse du quark top sont présentées. Une mesure de la masse du quark top est extraite en utilisant une définition de la masse calibrée à l'échelle partonique. / Discovered in 1995 at Fermilab, top quark is the last quark discovered. The measurement of its properties allows to test Standard Model predictions and to constraint Higgs boson mass. Due to its properties, the top quark is a privileged partner in the search for New Physics particles expected around TeV scale. This thesis, performed using the ATLAS detector at LHC, describes the different methods developed in order to measure precisely the top quark mass in its semileptonic decay. Two reconstruction methods are presented as well as a dedicated one based on Boosted Decision Trees. Its performances are quantified The precise measurement of the top quark mass needs a deep understanding of the jet energy scale. This thesis presents two strategies to calibrate light and b jets to the partonic scale. The performance of a kinematical fit applied to top mass measurement are presented. A precise measurement of the top quark mass is done using a calibrated scale to the partonic level.
18

Mesures de masse autour du 78Ni et nouveau traitement de l'équilibre statistique nucléaire pour l'étude des supernovae à effondrement de coeur / Mass measurements around 78Ni and new treatment of the nuclear statistical equilibrium for the study of core-collapse supernovae

Giraud, Simon 26 September 2019 (has links)
La thèse porte sur l’étude des supernovae à effondrement de coeur (CCSN). D’abord, nous avons cherché à modéliser la composition du coeur de l’étoile massive lors de son effondrement. Nous avons élaboré un nouveau traitement de l’équilibre statistique nucléaire à partir d’une équation d’état basée sur l’approximation de noyau unique (Lattimer et Swesty, LS). Cela permet d’obtenir une description plus réaliste de la distribution des noyaux constitutifs du coeur et de quantifier plus spécifiquement le rôle des masses nucléaires. Les distributions obtenues avec la fonctionnelle de masse originelle (LS) et celles obtenues à partir des modèles de masse tels que HFB-24 et DZ10 ont été comparées pour plusieurs conditions thermodynamiques d’une trajectoire typique de CCSN. Les différences de composition pouvant conduire à des déviations sur le taux de capture électronique allant jusqu’à ∼25%, il est apparu important de définir un modèle de masse réaliste à utiliser pour la simulation de CCSN. Pour cela, nous avons réalisé des mesures de masse de précision dans la région d’intérêt, avec un double piège de Penning auprès de l’installation IGISOL (située à Jyväskylä, Finlande). Cinq nouveaux excès de masse ont été déterminés pour les noyaux suivants : 69m,70Co, 74,75Ni et 76mCu. La précision a été améliorée pour cinq autres : 67Fe, 69Co, 76,78Cu, 79mZn. Enfin, nous avons confirmé les valeurs obtenues par des études récentes pour le 77Cu et le 79Zn. Dès lors, les valeurs expérimentales des gaps nucléaires Z=28 et N=50 ont été comparées aux résultats prédits par DZ10 et HFB-24. Ce dernier modèle reproduit mieux l’évolution des gaps en question. De fait, HFB-24 a été utilisé dans notre nouveau traitement statistique, que nous avons implémenté dans une simulation hydrodynamique existante de CCSN. Au final, nous avons observé un impact modéré du modèle de masse sur la composition du coeur en effondrement. Par ailleurs, nous avons montré que ces différences de composition ont peu d’effet sur la dynamique d’effondrement, celle-ci semble plus affectée par le taux de capture électronique. Les études futures devraient se focaliser plutôt sur ce paramètre. / The thesis sets itself in the framework of the study of core-collapse supernovae (CCSN). First, the modeling of the composition of the core of a massive star during its collapse has been investigated. To this aim, we have built a new treatment of the nuclear statistical equilibrium starting from a single-nucleus approximation equation of state (Lattimer and Swesty, LS). This allows a more realistic description of the nuclear distribution inside the core and, more specifically, to quantify the role of the nuclear masses. The distributions obtained with the original mass functional (LS) and those obtained with HFB-24 and DZ10 mass models have been compared for several thermodynamic conditions of a typical CCSN trajectory. The differences in the composition could lead up to ∼25% deviations in the electron-capture rate, thus showing the need to identify a proper mass model to use in CCSN simulations. Therefore, we performed high precision mass measurements in the nuclear mass region of interest, via a double Penning trap at the IGISOL facility (Jyväskylä, Finland). Five new mass excess were determined for the following nuclei : 69m,70Co, 74,75Ni and 76mCu. The precision has been improved for five others : 67Fe, 69Co, 76,78Cu and 79mZn. Finally, we have confirmed the values obtained by recent studies for 77Cu and 79Zn. The experimental values of the nuclear gaps for Z=28 and N=50 have been compared with the results predicted by DZ10 and HFB-24. The latter model better reproduces the evolution of these gaps. Therefore, HFB-24 was used in our new statistical treatment, that we implemented in an existing CCSN hydrodynamical simulation. We have observed a moderated impact of the mass model on the composition of the collapsing core. Moreover, we found that the differences in composition have small effect on the collapse dynamics, which appears to be more sensitive to the electron-capture model. Further studies should thus focus on this parameter.

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