Prediction of transonic flutter for a supercritical wing by modified strip analysis and comparison with experiment

Use of a supercritical airfoil can adversely affect wing flutter speeds in the transonic range. As adequate theories for three dimensional unsteady transonic flow are not yet available, the modified strip analysis was used to predict the transonic flutter boundary for the supercritical wing. The steady state spanwise distributions of section lift curve slope and aerodynamic center, required as input for the flutter calculations, were obtained from pressure distributions. The calculated flutter boundary is in agreement with experiment in the subsonic range. In the transonic range, a transonic bucket is calculated which closely resembles the experimental one with regard to both shape and depth, but it occurs at about 0.04 Mach number lower than the experimental one

Isotopic composition of Murchison organic compounds: Intramolecular carbon isotope fractionation of acetic acid. Simulation studies of cosmochemical organic syntheses

Recently, in our laboratories, samples of Murchison acetic acid were decarboxylated successfully and the carbon isotopic composition was measured for the methane released by this procedure. These analyses showed significant differences in C-13/C-12 ratios for the methyl and carboxyl carbons of the acetic acid molecule, strongly suggesting that more than one carbon source may be involved in the synthesis of the Murchison organic compounds. On the basis of this finding, laboratory model systems simulating cosmochemical synthesis are being studied, especially those processes capable of involving two or more starting carbon sources

Teaching in groups in grade III.

Thesis (Ed.M.)--Boston University N.B.:Pages 28, 144 and 145 are missing from original thesis

Distribution of moisture in reconstructed oil paintings on canvas during absorption and drying: a neutron radiography and NMR study

Moisture is a driving factor in the long-term mechanical deterioration of canvas paintings, as well as for a number of physico–chemical degradation processes. Since the 1990s a number of publications have addressed the equilibrium hygroscopic uptake and the hygro-mechanical deformation of linen canvas, oil paint, animal glue, and ground paint. In order to visualise and quantify the dynamic behaviour of these materials combined in a painting mock-up or reconstruction, we have performed custom-designed experiments with neutron radiography and nuclear magnetic resonance (NMR) imaging. This paper reports how both techniques were used to obtain spatially and temporally resolved information on moisture content, during alternate exposure to high and low relative humidity, or in contact with liquids of varying water activities. We observed how the canvas, which is the dominant component in terms of volumetric moisture uptake, absorbs and dries rapidly, and, due to its low vapour resistance, allows for vapour transfer towards the ground layer. Moisture desorption was generally found to be faster than absorption. The presence of sizing glue leads to a local increase of moisture content. It was observed that lining a painting with an extra canvas results in a damping effect: i.e. absorption and drying are significantly slowed down. The results obtained by NMR are complementary to neutron radiography in that they allow accurate monitoring of water ingress in contact with a liquid reservoir. Quantitative results are in good agreement with adsorption isotherms. The findings can be used for risk analysis of paintings exposed to changing micro-climates or subjected to conservation treatments using water. Future studies addressing moisture-driven deformation of paintings can make use of the proposed experimental techniques

Characterization of growth and metabolism of the haloalkaliphile Natronomonas pharaonis

Natronomonas pharaonis is an archaeon adapted to two extreme conditions: high salt concentration and alkaline pH. It has become one of the model organisms for the study of extremophilic life. Here, we present a genome-scale, manually curated metabolic reconstruction for the microorganism. The reconstruction itself represents a knowledge base of the haloalkaliphile's metabolism and, as such, would greatly assist further investigations on archaeal pathways. In addition, we experimentally determined several parameters relevant to growth, including a characterization of the biomass composition and a quantification of carbon and oxygen consumption. Using the metabolic reconstruction and the experimental data, we formulated a constraints-based model which we used to analyze the behavior of the archaeon when grown on a single carbon source. Results of the analysis include the finding that Natronomonas pharaonis, when grown aerobically on acetate, uses a carbon to oxygen consumption ratio that is theoretically near-optimal with respect to growth and energy production. This supports the hypothesis that, under simple conditions, the microorganism optimizes its metabolism with respect to the two objectives. We also found that the archaeon has a very low carbon efficiency of only about 35%. This inefficiency is probably due to a very low P/O ratio as well as to the other difficulties posed by its extreme environment

Statistical Inference for Valued-Edge Networks: Generalized Exponential Random Graph Models

Across the sciences, the statistical analysis of networks is central to the production of knowledge on relational phenomena. Because of their ability to model the structural generation of networks, exponential random graph models are a ubiquitous means of analysis. However, they are limited by an inability to model networks with valued edges. We solve this problem by introducing a class of generalized exponential random graph models capable of modeling networks whose edges are valued, thus greatly expanding the scope of networks applied researchers can subject to statistical analysis

L’Échelle du climat de prévention de la violence : traduction, adaptation et évaluation psychométrique de la version canadienne-française

Introduction: Violence in psychiatric settings has negative consequences on patients, staff, and the institution alike. Efforts to prevent violence cannot currently be assessed due to a lack of suitable indicators. The Violence Prevention Climate Scale (VPC-14) is a validated tool that can be filled out by both staff and patients to assess the violence prevention climate in mental health care units. Objective: This study aimed to conduct the translation and adaptation of the VPC-14 to a French Canadian context, and to assess its psychometric properties in general and forensic psychiatric settings. Methods: This study followed a transcultural approach for validating measuring instruments. Psychometric properties were assessed in 308 patients and staff from 4 mental health and forensic hospitals in Quebec (Canada). Content validity was assessed using a bilingual participant approach. Internal validity was examined through exploratory factor analysis and internal consistency for each care setting using Cronbach’s alpha coefficient analysis. Results: The Échelle modifiée du climat de prévention de la violence [Modified Violence Prevention Climate Scale] (VPC-M-FR) consists of 23 items with a 3-factor structure: 1) staff action, 2) patient action, and 3) the therapeutic environment. Cronbach’s alphas ranging from 0.69 to 0.89 were obtained for the internal consistency of the scale. Discussion and conclusion: The VPC-M-FR has satisfactory psychometric properties for measuring the violence prevention climate in mental health and forensic settings. By measuring the violence prevention climate from the standpoint of patients and staff, targeted preventive measures can be implemented to improve safety for all.Introduction : La violence en milieu psychiatrique entraîne des conséquences néfastes pour les patients, les intervenants et les organisations. Pourtant, les efforts pour la prévenir ne peuvent être évalués faute d’indicateurs adéquats. Le Violence Prevention Climate Scale (VPC-14), complété par les intervenants et les patients, est un outil validé qui évalue le climat de prévention de violence. Objectif : Cette étude vise à traduire et adapter le VPC-14 au contexte québécois et à en vérifier la fiabilité et la validité en psychiatrie générale et légale. Méthodes : En se basant sur la méthode de validation transculturelle d’instruments de mesure, les propriétés psychométriques ont été évaluées auprès de 308 patients et intervenants de 4 hôpitaux et instituts de santé mentale et médico-légale québécois. La validité de construit a été examinée par une analyse factorielle exploratoire et la cohérence interne par l’analyse du coefficient alpha de Cronbach. Résultats : L’Échelle modifiée du climat de prévention de la violence (VPC-M-FR) comprend 23 énoncés avec une structure à 3 facteurs : 1) les actions des intervenants, 2) les actions des patients et 3) l’environnement thérapeutique. Des coefficients alpha de Cronbach variant de 0,69 à 0,89 ont été obtenus pour la consistance interne de l’échelle. Discussion et conclusion : Le VPC-M-FR possède des propriétés psychométriques satisfaisantes pour mesurer le climat de prévention de la violence en milieu de santé mentale et médico-légal. En tenant compte de la perspective des intervenants et des patients, des interventions ciblées de prévention pourront être mises en œuvre afin d’améliorer la sécurité de tous

Exploring Gusev Crater with spirit: Review of science objectives and testable hypotheses

Gusev Crater was selected as the landing site for the Mars Exploration Rover (MER) Spirit mission. Located at the outlet of Ma'adim Vallis and 250 km south of the volcano Apollinaris Patera, Gusev is an outstanding site to achieve the goals of the MER mission. The crater could have collected sediments from a variety of sources during its 3.9 Ga history, including fluvial, lacustrine, volcanic, glacial, impact, regional and local aeolian, and global air falls. It is a unique site to investigate the past history of water on Mars, climate and geological changes, and the potential habitability of the planet, which are central science objectives of the MER mission. Because of its complex history and potential diversity, Gusev will allow the testing of a large spectrum of hypotheses with the complete suite of MER instruments. Evidence consistent with long-lived lake episodes exist in the landing ellipse area. They might offer a unique opportunity to study, for the first time, Martian aqueous sediments and minerals formed in situ in their geological context. We review the geological history and diversity of the landing site, the science hypotheses that can be tested during the MER mission, and the relevance of Gusev to the MER mission objectives and payload

Geological and Hydrogeological Characterization of Springs in a DSGSD Context (Rodoretto Valley – NW Italian Alps)

As continuous groundwater monitoring in the upper sector of Rodoretto Valley (Germanasca Valley, Italian Western Alps) is hampered by logistical problem of data collection during winter and spring months, the only tools currently available to derive hydrogeological information are non-continuous and non-long-term dataset of spring discharge (Q), temperature (T) and electrical conductivity (EC). In order to quantity aquifer groundwater reserve, available Q dataset of a small mountain spring (Spring 1 CB) was investigated by applying the analytical solutions developed by Boussinesq (J Math Pure Appl 10:5–78, 1904) and Maillet (Essais dı’hydraulique souterraine et fluviale, vol 1. Herman et Cie, Paris, 1905); T and EC datasets were also used to provide qualitative information about the nature of the aquifer that supplies the spring. The outcomes of the elaborations highlighted the limits of applicability of these methods in the presence of a non-continuous Q dataset: both Boussinesq (J Math Pure Appl 10:5–78, 1904) and Maillet (Essais dı’hydraulique souterraine et fluviale, vol 1. Herman et Cie, Paris, 1905) estimated that discharge values as a function of recession time were found to be consistently lower than the available discharge ones and the estimated groundwater volumes stored over time above the spring level turned out to be underestimated. Continuous (hourly value) and long-term Q, EC and T values are, therefore, needful to correctly quantify and to make a proper management of groundwater resources in mountain areas