<p>A beam of 250A MeV ¹⁷O ions was scattered from argon and xenon targets. The large excess of fast neutrons compared with statistical model calculations that was observed earlier for xenon, was confirmed and found for argon as well. Analysis and calculations show that a considerable fraction of these neutrons can be interpreted as coming from direct knock-out reactions.</p><p>The angular distributions do not support the suggestion of using fast heavy ion scattering as a probe for the study of the neutron skin in nuclei. While the basic idea that a heavy projectile tends to sample the neutron wave function near the surface of the nucleus is sound, the measured neutron distribution is not as distinct as suggested by the previous experiment. This makes it difficult to distinguish direct reactions from other channels, such as semi-direct decay of giant resonances.</p><p>The improvements in the experimental methods have made the concept of using the CELSIUS storage and cooler ring as an internal magnetic spectrometer attractive for other of experiments presently being prepared.</p>

<p>Two aspects of applied nuclear physics have been studied in this thesis; Monte Carlo simulations for high-sensitivity monitoring of radioactive xenon and high-accuracy neutron-proton scattering measurements for neutron physics applications and fundamental physics.</p><p>The Monte Carlo simulations have been performed for two systems for detection of radioactive xenon, using the MCNP code. These systems, designed for monitoring of violations of the Comprehensive Nuclear-Test-Ban Treaty, are based on coincident detection of electrons and gamma rays, emitted in beta decay of xenon nuclides produced in nuclear weapons explosions. In general, the simulations describe test data well, and the deviations from experimental data are understood. </p><p>The neutron-proton scattering measurements have been performed by measuring the differential <i>np</i> scattering cross section at 96 MeV in the angular range θ_c.m.= 20° – 76°. Together with an earlier data set at the same energy, covering the angles θ_c.m.= 74° – 180°, a new data set has been formed in the angular range θ_c.m.= 20° – 180°. This extended data set has been normalised to the experimental total <i>np</i> cross section, resulting in a renormalisation of the earlier data of 0.7 %, which is well within the stated normalisation uncertainty for that experiment. The results on forward <i>np</i> scattering are in reasonable agreement with theory models and partial wave analyses and have been compared with data from the literature.</p>

Dans les milieux ionisés existe un grand nombre d’espèces chimiques. Beaucoup sont en quantité minoritaire mais jouent pourtant, par leur grande réactivité, un rôle essentiel dans les processus de transformation chimique. Cette étude s’intéresse à la structure et à la dynamique des ions moléculaires, ainsi qu’aux collisions réactives pour des systèmes intervenant dans les atmosphères planétaires et dans le milieu interstellaire, comme les réactions mettant en jeu le monoxyde de carbone. Des modélisations numériques sont nécessaires à la préparation des expériences de fusion thermonucléaire. Enrichis par les résultats expérimentaux, concernant les ions d’hydrocarbures tels que le méthane, ils fournissent une aide pour l'interprétation des phénomènes observés dans les tokamaks. L’identification des réactions physiques à l’origine de la présence de particules dans le plasma est une étape importante afin de comprendre les environnements ionisés. Les systèmes examinés à Louvain-la-Neuve sont donc choisis pour leur intérêt immédiat en astrophysique ou en physique des plasmas. Alors que la connaissance des processus d'ionisation par impact d'électrons d’espèces atomiques ou ioniques simples est bien établie, ce n’est pas encore le cas lorsque la cible primaire est un ion moléculaire. L'existence d'au moins un degré de liberté supplémentaire rend possible la dissociation de l'ion moléculaire initial en plusieurs fragments, une partie de l’énergie potentielle est alors transférée sous forme d’énergie cinétique aux produits. En conséquence, ceux-ci sont généralement distribués dans de larges gammes angulaire et énergétique. L’analyse fine des distributions permet d’étudier les détails de la collision électronique. L’expérience a pour thématique majeure la mesure des sections efficaces absolues en fonction de l’énergie des électrons projectiles incidents, pour des réactions impliquant des espèces ioniques polyatomiques. L’observation des seuils de réaction et de l’énergie cinétique des fragments permet de déterminer la zone de Franck-Condon accessible et les états moléculaires impliqués dans les processus considérés. Les travaux réalisés au laboratoire ont démontré que l'appareillage existant est bien approprié à ce type d’étude. A un niveau plus fondamental, l’examen comparatif minutieux des présentes mesures, des résultats issus d’autres expériences et des prédictions des formalismes semi-empiriques, permet d’améliorer la connaissance des phénomènes collisionnels.

In order to obtain a good performance and predict the properties of alloys, it is necessary to control the contents of alloying elements and to evaluate a largest inclusion in the product. Thus, improved techniques for both control of alloy elements and evaluation of the large inclusion in products will enable us to provide better qualities of the final products. In the case of one Ni alloy, (NW2201, &gt;99 mass%Ni), the precise control technique of Mg content is important to obtain a good hot-workability. Hereby, the slag/metal reaction experiments in a laboratory have been carried out at 1873 K, so that the equilibrium Mg content and kinetic behavior can be understood. More addition of Al in the melt as well as higher CaO/Al2O3 value of slag resulted in higher amount of Mg content in Ni. For the same conditions of Al content and slag composition, the mass transfer coefficient of Mg in molten Ni was determined as 0.0175 cm/s. By applying several countermeasures regarding the equilibrium and kinetic process to the plant trials, the value of the standard deviation for the Mg content in an alloy was decreased till 0.003 from 0.007 mass%. The size measurements of largest inclusions in the various alloys (an Fe-10mass%Ni alloy, 17CrMo4 of low-C steel and 304 stainless steel) were carried out by using statistics of extreme values (SEV). In order to improve the prediction accuracy of this method, three dimensional (3D) observations were applied after electrolytic extraction. In addition, the relationship of extreme value distribution (EVD) in the different stages of the production processes was studied. This was done to predict the largest inclusion in the products at an early stage of the process. A comparison of EVDs for single Al2O3 inclusion particles obtained by 2D and 3D observations has clarified that 3D observations result in more accurate EVD because of the absence of pores. Also, it was found that EVD of clusters were larger than that of single particles. In addition, when applying SEV to sulfide inclusions with various morphologies, especially for elongated sulfides, the real maximum sizes of them were able to be measured by 3D observations. Geometrical considerations of these particles clarified the possibility of an appearance of the real maximum inclusion sizes on a cross section to be low. The EVDs of deoxidation products in 304 stainless steel showed good agreement between the molten steel and slab samples of the same heat. Furthermore, the EVD of fractured inclusion lengths in the rolled steel were estimated from the initial sizes of undeformed inclusions which were equivalent with fragmented inclusions. On the other hand, from the viewpoint of inclusion width, EVD obtained from perpendicular cross section of strips was found to be useful to predict the largest inclusion in the final product with less time consumption compared to a slab sample. In summary, it can be concluded that the improvement of the techniques by this study has enabled to precisely control of alloy compositions as well as to evaluate the largest inclusion size in them more accurately and at an earlier stage of the production process. / QC 20101222

Two aspects of applied nuclear physics have been studied in this thesis; Monte Carlo simulations for high-sensitivity monitoring of radioactive xenon and high-accuracy neutron-proton scattering measurements for neutron physics applications and fundamental physics. The Monte Carlo simulations have been performed for two systems for detection of radioactive xenon, using the MCNP code. These systems, designed for monitoring of violations of the Comprehensive Nuclear-Test-Ban Treaty, are based on coincident detection of electrons and gamma rays, emitted in beta decay of xenon nuclides produced in nuclear weapons explosions. In general, the simulations describe test data well, and the deviations from experimental data are understood. The neutron-proton scattering measurements have been performed by measuring the differential np scattering cross section at 96 MeV in the angular range θc.m.= 20° – 76°. Together with an earlier data set at the same energy, covering the angles θc.m.= 74° – 180°, a new data set has been formed in the angular range θc.m.= 20° – 180°. This extended data set has been normalised to the experimental total np cross section, resulting in a renormalisation of the earlier data of 0.7 %, which is well within the stated normalisation uncertainty for that experiment. The results on forward np scattering are in reasonable agreement with theory models and partial wave analyses and have been compared with data from the literature.

A beam of 250A MeV 17O ions was scattered from argon and xenon targets. The large excess of fast neutrons compared with statistical model calculations that was observed earlier for xenon, was confirmed and found for argon as well. Analysis and calculations show that a considerable fraction of these neutrons can be interpreted as coming from direct knock-out reactions. The angular distributions do not support the suggestion of using fast heavy ion scattering as a probe for the study of the neutron skin in nuclei. While the basic idea that a heavy projectile tends to sample the neutron wave function near the surface of the nucleus is sound, the measured neutron distribution is not as distinct as suggested by the previous experiment. This makes it difficult to distinguish direct reactions from other channels, such as semi-direct decay of giant resonances. The improvements in the experimental methods have made the concept of using the CELSIUS storage and cooler ring as an internal magnetic spectrometer attractive for other of experiments presently being prepared.

Data on elastic scattering of 96 MeV neutrons from 56Fe, 89Y and 208Pb in the angular interval 10-70° are presented. The previously published data on 208Pb have been extended, as a new method has been developed to obtain additional information at the most forward angles. The results are compared with phenomenological and microscopic optical potentials. The theory predictions are in general in good agreement with the experimental data. A study of the deviation of the zero-degree cross section from Wick's limit has been performed. The data on 208Pb are in agreement with Wick's limit, while those on lighter nuclei overshoot the limit significantly. A novel analysis method has been developed to obtain the inelastic neutron emission cross sections from the existing 56Fe data. The method is based on folding a trial spectrum with the response of the detector setup. The data cover the angular interval 26-65° and an excitation energy range of 0-45 MeV, ranges hitherto not studied. The results are compared with nuclear model predictions and found to be in good agreement with the experimental data.

Every year about half a million women die from complications of pregnancy, parturition and puerperium, most of which are preventable. The purpose of this thesis was to chart the distribution and decline in maternal mortality in Sweden between 1751 and 1980, and furthermore to characterize positive (predisposing) factors and negative (protective) factors of maternal mortality. Maternal mortality declined from 900 to 6.6 per 100,000 live births in these 230 years. Maternal deaths accounted for 10070 of all female deaths in the reproductive ages between 1781 and 1785, but only 0.2.0/0 between 1976 and 1980. However, in the 19th century 40-450/0 of the female deaths in the most active childbearing ages were maternal deaths. The children left motherless had an extremely high mortality. Indirect maternal deaths and puerperal sepsis accounted for the bulk of maternal deaths in the rural areas. Only a minority of maternal deaths occurred in lying-in hospitals. Midwifery services in rural areas and antiseptic techniques were most effective in preventing maternal deaths during the late 19th century. The changing distribution ofage and parity amongst the parturients had a definite impact on the mortality decline, enhanced by time, contributing to 500/0 of the mortality decline over the last 15 years. The expontential decline of cause-specific mortality and case fatality rates during the last 40 years is furthermore explained by the emergence ofmodern medicine - antibiotics, antenatal and obstetric care. The earlier serious problem of illegal abortions was eradicated by legislation and changes in hospital practice. The maternal mortality decline has levelled out during the 1970s, the relative importance of embolism as a cause of death is increasing. Advanced age and intercurrent disease are the most difficult risk factors to overcome. To conclude, this study indicates that the reason why maternal mortality has declined faster than otherhealth indices is that the major part of the maternal deaths can be prevented by medical technology, including family planning, antenatal and obstetric care. This experience should be of interest to developing countries where high rates of maternal mortality prevails.

Pregnancy and birth are not only physiological processes but also socially and culturally organized events. Pregnancy is an individual experience as well as the focus of collective concerns and values. In this dissertation the pregnant body is understood as an arena of social truths and contesting perspectives: a public stage where different perspectives on medical technology, risk and gender are acted out. Swedish maternity care dominates the arena, and women have to adjust to the authority of medical knowledge. This, however, does not mean that women comply without questions. As the study shows they struggle for voice and agency which is reflected in pregnant women’s differing views and uses of biomedical knowledge and technology. Although the discourse on pregnancy and birth is highly ideological and marked by strong opinions, pregnant women in practice tend to be motivated by pragmatics rather than ideology. In order to understand the complexities and nuances of reproductive culture in Sweden, we need to move beyond distinctions such as the one between technology and the body, and instead focus on the experiential world of pregnant women in which technology is an integral part in everyday life and therefore taken for granted rather than problematised. The thesis is based on fieldwork at a maternity care center and interviews with pregnant women. Furthermore, discussion groups on the Internet and debates in mass media have been valuable sources of information. / Avhandlingen finns att köpa som tryckt bok för 120 SEK exkl. frakt. Maila birgitta.hellmark@comhem.se

Afin de répondre au problème de santé publique que représente l'asthme, l'imagerie tomodensitométrique associé aux traitements informatiques permettent la quantification et le suivi des dommages subis par les bronches. Le but de l'imagerie bronchique, lors d'un examen de type scanner-CT est de disposer de mesures fiables et reproductibles des différents paramètres bronchiques qui sont des marqueurs de l'importance de la pathologie et de son évolution sous traitements. Ces marqueurs correspondent à deux mesures LA ( Lumen Area) et WA ( Wall Area) prises sur des coupes perpendiculaires à la bronche. La mise en place d'une chaîne de traitements constitué de maillons d'extraction et de squelettisation de l'arbre trachéo-bronchique permet l'obtention de tels mesures. Durant cette thèse nous nous sommes focalisés sur la création d'une chaîne de traitements en proposant une contribution sur chacun des maillons. Notre chaîne est modulable et adaptée au travail en 4D (différentes phases respiratoires) et à fait l'objet d'une implémentation logiciel intitulée Neko4D.