Analysis of an Earthquake-Initiated-Transient in a PBR

One of the Design Basis Accidents (DBA) for a Pebble Bed Reactor has been identified as the “Safe shutdown earthquake with core conduction cooling to passive mode of Reactor Cavity Cooling System.” A new methodology to analyze this particular DBA has been developed at the Idaho National Laboratory (INL). During the seismic event the reactor core experiences the densification of the pebbles, which produce small reactivity insertions due to the effective fuel densification. In addition, a decrease in the active core height results in the relative withdrawal of the control rods, which are assumed to remain stationary during the transient. The methodology relies on the dynamic re-meshing of the core during the transient to capture the local packing fraction changes and their corresponding effects on temperature and reactivity. The core re-meshing methodology is based on the velocity profiles of the pebbles in the core, which were obtained with the INL’s pebble mechanics code PEBBLES. The methodology has been added to the coupled code system CYNOD-THERMIX-KONVEK. The reactor power calculation is further improved with the use of the new advanced TRISO fuel model to better approximate the temperatures in the fuel kernels. During the transient the core is brought back to a safe condition by the strong Doppler feedback from local temperature increases

Digital planning of composite customized veneers using Digital Smile Design: Evaluation of its accuracy and manufacturing

Objectives: This study aimed to evaluate the production of customized composite veneers starting from a two-dimensional (2D) digital preview using the Digital Smile System (DSS). Material and Methods: A photographic examination of 30 patients was performed by taking two digital pictures of the face and a digital preview through the DSS. Moreover, optical scans of the dental arches were obtained and the data were entered into a three-dimensional (3D) software to prepare a virtual preview. The standard tessellation language files were sent for production using CAD-CAM technology. The Friedman test, Bonferroni, and Dunn post hoc tests were used, comparing the linear measurements of the 2D and 3D plans and the final veneers (α =.05). Results: Significant differences emerged between the pictures and digital scans on the mesial–distal widths of the lateral incisors and canine. Linear measurements in the 2D plan were significantly different from those of the 3D plan, except for the height measures of incisors. No significant changes were found on comparing the parameters of the 2D and 3D plans with those of the final pieces. Conclusions: The customized veneers were clinically adequate and similar to 2D and 3D plans, although significant differences emerged between the picture and digital scans as well as between the 2D and 3D plans

The legacy of Corrado Gini in population studies

This volume contains 12 papers that range over many different research subjects, taking in many of the population questions that, directly or indirectly, absorbed Corrado Gini as demographer and social scientist over several decades. They vary from the analysis of the living conditions and behaviours of the growing foreign population (measurements and methods of analysis, socio-economic conditions and health, ethnic residential segregation, sex-ratio at birth), to studies on the homogamy of couples; from population theories (with reference to the cyclical theory of populations) to the modelling approach to estimating mortality in adult ages or estimating time transfers, by age and sex, related to informal child care and adult care; from historical studies that take up themes dear to Gini (such as the estimates of Italian military deaths in WWI), to the application of Gini’s classical measurements to studying significant phenomena today (transition to adulthood and leaving the parental home, health care, disabled persons and social integration). The subjects and measurements that appear here are not intended to exhaust the broad spectrum of Gini’s research work in the demographic and social field (nor could they), but they can make up a part of the intersection between his vast legacy and some interesting topics in current research, some of which were not even imaginable in the mid twentieth century. Looking at the many contributions that celebrated Gini in Treviso and thinking about his legacy, it seems possible to identify at least two typologies of approach, to be found in this issue of the journal, too. On the one hand, there are contributions that aim to retrieve and discuss themes, methodologies and measurements dealt with or used by Gini so as to evaluate their present relevance and importance in the current scholarly debate. On the other, there are contributions that deal with topics that are far from Gini’s work, as they study very recent phenomena, but actually, among other things, make use of methods and indicators devised by Gini that are now so much part of the common currency of methodology, so they don’t require explicit reference to their Author

PRISMATIC CORE COUPLED TRANSIENT BENCHMARK

The Prismatic Modular Reactor (PMR) is one of the High Temperature Reactor (HTR) design concepts that have existed for some time. Several prismatic units have operated in the world (DRAGON, Fort St. Vrain, Peach Bottom) and one unit is still in operation (HTTR). The deterministic neutronics and thermal-fluids transient analysis tools and methods currently available for the design and analysis of PMRs have lagged behind the state of the art compared to LWR reactor technologies. This has motivated the development of more accurate and efficient tools for the design and safety evaluations of the PMR. In addition to the work invested in new methods, it is essential to develop appropriate benchmarks to verify and validate the new methods in computer codes. The purpose of this benchmark is to establish a well-defined problem, based on a common given set of data, to compare methods and tools in core simulation and thermal hydraulics analysis with a specific focus on transient events. The benchmark-working group is currently seeking OECD/NEA sponsorship. This benchmark is being pursued and is heavily based on the success of the PBMR-400 exercise

Primary Raynaud's phenomenon in an infant: a case report and review of literature

Raynaud's phenomenon (RP) is an extremely unusual finding in early infancy. In the present report we describe a one-month-old previously healthy male infant who presented with unilateral acrocyanosis. Although infantile acrocyanosis is known to be a benign and self-resolving condition, it is generally bilateral and symmetric. The unilateral nature of the acrocyanosis was an atypical finding in this infant. Consequently, he was closely monitored to evaluate the progression of his acrocyanosis. Based on his benign clinical course and failure to demonstrate other etiologies contributing to his acrocyanosis, he was diagnosed to have primary RP. Due to the rarity of RP in children, we review the progress in understanding the pathophysiology, epidemiology and management of RP and additionally discuss the differential diagnosis of unilateral and bilateral acrocyanosis in infants

Intentions on desired length of stay among immigrants in Italy

Abstract The decision to emigrate from the country of origin may not be a permanent one: migrants can decide to return home or to emigrate to a third country. This phenomenon, established for some time in certain other European countries, has become an important one for Italy only recently. This paper contributes to the knowledge of migrants’ intentions in two ways: on the one hand, it analyses the factors associated with indecision about future plans; on the other, it focuses on the desired length of stay and its relationship with attachments (family, economic, socio-cultural and psychological) to host and home country. We used two logistic regression models: one for migrants’ indecision and the other for migrants’ desired length of stay. The data were collected by survey, coordinated by the ISMU Foundation and conducted in 2008 and 2009 with more than 12,000 migrants living in Italy. According to our results, indecision seems to be associated with an intermediate phase of migration at the early stage of family development in the case of negative balance of the migration experience, while attachment to the host country is associated with longer stay, and no attachments or attachment to the country of origin are associated with shorter stay

Implant-Supported Prosthetic Therapy of an Edentulous Patient: Clinical and Technical Aspects

The purpose of this article is to show how to implement an implant-supported prosthetic overdenture using a digital workflow. Esthetic previewing using a specific software, guided-surgery, construction of the prosthesis, and the esthetic finalization are described in this article. Patients suffering from severe loss of bone and soft tissue volume could benefit from the construction of an overdenture prosthesis as a feasible therapeutic choice for functional and esthetic issues of the patient

Migrating with Special Needs? Projections of Flows of Migrant Women with Female Genital Mutilation/Cutting Toward Europe 2016-2030

Female genital mutilation/cutting (FGM/C) is a rising issue in western societies as a consequence of international migration. Our paper presents demography-driven projections of female flows with FGM/C from each practicing country to each EU28 member state for the 3 sub-periods 20162020, 2021-2025, and 2026-2030, with the aim of supporting resource planning and policy making. According to our projections, the EU28 countries will receive a flow of around 400,000 female migrants between 2016 and 2020, and around 1.3 million female migrants between 2016 and 2030 from FGM/C practicing countries. About one-third of them, corresponding to an estimated 127,000 between 2016 and 2020, and more than 400,000 between 2016 and 2030 will have undergone FGM/C before migration. Among these female flows, slightly more than 20% is expected to be made up of girls aged 0-4. According to the expected age at arrival, 20% of these girls are expected to have already undergone FGM/C, while slightly less than 10% are to be considered potentially at risk of undergoing FGM/C after migration. As the number of women with FGM/C in Europe is expected to rise at quite a fast rate, it is important to act timely by designing targeted interventions and policies at the national and at the European level to assist cut women and protect children. Such measures are particularly compelling in France, Italy, Spain, UK, and Sweden that are expected to be the most affected countries by migration from FGM/C practicing countrie

(Ri)conoscere le Mgf. Riflessioni sulle possibilità di quantificare un fenomeno elusivo”

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