Implementation of radiation shielding calculation methods. Volume 1: Synopsis of methods and summary of results

The work performed in the following areas is summarized: (1) Analysis of Realistic nuclear-propelled vehicle was analyzed using the Marshall Space Flight Center computer code package. This code package includes one and two dimensional discrete ordinate transport, point kernel, and single scatter techniques, as well as cross section preparation and data processing codes, (2) Techniques were developed to improve the automated data transfer in the coupled computation method of the computer code package and improve the utilization of this code package on the Univac-1108 computer system. (3) The MSFC master data libraries were updated

Monaci e monasteri nella storia di Roma attraverso le fonti della chiesa romana (secoli VI-X)

Monaci e monasteri nella storia di Roma attraverso le fonti della chiesa romana (secoli VI-X)The study, mainly conducted on sources close to the institution Roman church (Liber Pontificalis, Liber Diurnus, Ordines), seeks to understand what is the concept of monasticism that sources show and the place that they assign to it in the same church, following its development and collecting information useful to place the phenomenon also with respect to Roman society

Application of transport techniques to the analysis of NERVA shadow shields

A radiation shield internal to the NERVA nuclear rocket reactor required to limit the neutron and photon radiation levels at critical components located external to the reactor was evaluated. Two significantly different shield mockups were analyzed: BATH, a composite mixture of boron carbide, aluminum and titanium hydride, and a borated steel-liquid hydrogen system. Based on the comparisons between experimental and calculated neutron and photon radiation levels, the following conclusions were noted: (1) The ability of two-dimensional discrete ordinates code to predict the radiation levels internal to and at the surface of the shield mockups was clearly demonstrated. (2) Internal to the BATH shield mockups, the one-dimensional technique predicted the axial variation of neutron fluxes and photon dose rates; however, the magnitude of the neutron fluxes was about a factor of 1.8 lower than the two-dimensional analysis and the photon dose rate was a factor of 1.3 lower

De la portée de la « palatisation » en gbe et ses implications théoriques

Après avoir énuméré les différentes règles de « palatalisation » que l’on rencontre dans les différents parlers gbe sur les plans synchronique et diachronique, la présente étude suggère qu’il faudrait peut-être remplacer le terme « palatalisation » par « sibilantisation » pour refléter la diversité de ses manifestations concrètes. Mais plus que cela, cette étude tire les conséquences logiques de la portée du processus en gbe et les rattache à quelques questions d’universaux. Ainsi les hypothèses suivantes ont-elles été proposées : (i) que le processus ne se produit pas si la position générale de la langue n’est pas convexe; (ii) qu’il ne se produirait pas avec les autres voyelles s’il ne faisant de même avec les voyelles d’avant fermées; (iii) qu’il n’affecterait pas les fricatives sans affecter aussi les occlusives; et (iv) qu’il n’affecterait pas les consonnes antérieures sans les consonnes postérieures (du moins par le passé). Dans tous les cas, le processus passé en revue, loin d’être simple, est en fait non seulement complexe, mais encore multiple.After enumerating various "palatalisation" rules as they apply to various Gbe dialects synchronically and diachronically, the present paper suggests that perhaps the term "palatalisation" should be replaced with "sibilantisation" to cover the actual range of its manifestations. More importantly this study draws the logical consequences of the scope of the process in Gbe and relates them to some issues of universals. Thus the following hypotheses are put forwards: (i) that the process may not occur if the tongue body does not assume a convex position; (ii) that it may not take place with other vowels if it does not do same with the front close vowels; (iii) that it may not affect fricatives unless it also affects stops; and (iv) that it may not affect the anterior consonants without affecting the back ones (at least in the past). No doubt, the process reviewed, far from being a simple one, is in fact not only complex but also multiple

Web 2.0 Technologies for Classroom Instruction: High School Teachers\u27 Perceptions and Adoption Factors

Web 2.0 technologies have potential for teaching and learning, but show a slow rate of adoption in education. The purpose of this study was to examine the factors that contribute to high school teachers\u27 intention to use Web 2.0 technologies for classroom instruction. Research questions examined were (a) To what extent are high school teachers using Web 2.0 technologies for classroom instruction? (b) What opinions do high school teachers have regarding Web 2.0 technologies for classroom instruction? (c) Which factors best predict the decision of high school teachers to adopt or not Web 2.0 technologies for classroom instruction? The decomposed theory of planned behavior was used as theoretical framework. A survey design was employed adapting Ajjan and Hartshorne\u27s (2008) questionnaire. Participants were high school teachers from a specific school region of Miami-Dade County Public Schools. Data from 137 participants were analyzed using descriptive and multiple regression methods. Findings showed that teachers do not use these technologies: blogs 51.1%, wikis 36.5%, social networking 53.3%, social bookmarking 59.9%, and audio/video conferencing 41.6%. Many did not plan to use them at all. Regarding predictors of teachers\u27 behavioral intention to use Web 2.0 technologies: attitude, subjective norm, and perceived behavioral control were significant predictors, with attitude the strongest (β = .634); of the decomposed factors, perceived usefulness and compatibility were significant predictors. Teacher comments suggested that lack of equipment, lack of training, lack of funding, security issues, and firewalls were possible obstacles affecting perceived usefulness and compatibility

Evaluation of CT urography as a second-line investigation in patients presenting with visible haematuria in the Highland region

Over the years, a body of literature has developed that consistently shows how the liability of foreignness affects MNCs' performance. Institutional distance − regulatory, normative and cognitive − between the incomer and insiders has been identified as the likely source of the highest cost in doing business abroad. In this article, we draw on the existing literature but take the opposite perspective, looking instead at how various dimensions of proximity between local players increase MNC distance and foster local resistance. The study investigates two contexts and cases, India and Japan, at the time of foreign retailer entry and analyses the interplay between local proximity and local resistance. The analysis presents four dimensions of proximity, namely spatial proximity, relational proximity, identity proximity and inter-organizational proximity, which present the stiffest challenges to foreign retail ventures entering markets as newcomers

Synthesis of calculational methods for design and analysis of radiation shields for nuclear rocket systems

Eight computer programs make up a nine volume synthesis containing two design methods for nuclear rocket radiation shields. The first design method is appropriate for parametric and preliminary studies, while the second accomplishes the verification of a final nuclear rocket reactor design

Comment faire évoluer les conceptions des élèves ? Les températures de changement d'état de l'eau au cycle 3

Comment faire comprendre aux élèves que l'eau change d'état à des températures constantes et ce indépendamment de la température de l'environnement et de la puissance de chauffage de l'eau ? Les confrontations aux expériences et entre pairs ont un rôle fondamental dans le bouleversement des conceptions des élèves et dans la reconstruction du nouveau savoir. Notre étude, réalisée auprès d'une classe de CE2, a montré que, pour la majorité de la classe, les conceptions initiales ont évolué et le nouveau savoir s'est installé de manière stable et durable. Les résultats sont beaucoup plus mitigés pour l'autre partie de la classe : dans quelques cas, les conceptions initiales sont revenues ; dans d'autres, de nouvelles conceptions, ne correspondant pas au savoir visé, sont apparues

Non-local regularization of the reverse heat equation for digital images enhancement

In 1955 Kovasznay et al. proposed to enhance an image by reversing the heat equation. This process is highly unstable and blows up the noise. Thus an efficient deblurring depends crucially on accurate denoising. In this paper we investigate the use of neighborhood filters and of a recent variant, NL-means, to stabilize the reverse heat equation. We shall prove that adding to the heat equation a term involving the self-similarities of the image stabilizes the reverse heat equation. By experiments on good quality images, not artificially blurred, we will illustrate the feasibility of the method to reveal image details. In contrast with the various PDE’s for image enhancement, the non-local reverse heat equation thus introduced is linear