Preliminary studies of new Ti alloys with different Mo content

This work aims to investigate the mechanical characteristics and biocompatibility of two novel titanium alloys, Ti15Mo7Zr15Ta1Si and Ti20Mo7Zr15Ta0,75Si.These samples have previously undergone cutting, grinding, polishing, and chipping. The studied samples were subjected to electrochemical, metallographic and corrosion behavior. Ti15Mo7Zr15Ta1Si and Ti20Mo7Zr15Ta0.75Si, the study samples, have demonstrated high corrosion potentials, lower corrosion rates, and consequently higher corrosion resistance. In summary, this study's data indicates that both alloys exhibit good corrosion behavior

Étude expérimentale et numérique des joints hydrauliques

Ce travail est une contribution à l'étude du comportement des joints en translation. Un modèle numérique, basé sur la théorie inverse, est développé pour en prédire les performances. La principale contribution consiste dans le traitement des effets hydrodynamiques liés à la région d'entrée du contact. Les résultats numériques sont ensuite validés par comparaison avec lesmesures expérimentales. Ces dernières sont obtenues sur un dispositif original, conçu et réalisé au laboratoire INOE 2000 IHP de Bucarest. Ce banc reproduit les conditions réelles de fonctionnement d'un joint hydraulique et permet de mesurer la force de frottement à pression et vitesse constantes. La comparaison des résultats numériques et expérimentaux a été effectuéepour un joint de tige en forme de "U" à des pressions de service comprises entre 4 MPa et 20 MPa et pour deux vitesses de translation. Dans un premier temps, on a idéalisé le problème en considérant que les surfaces en contact tige-joint sont lisses. Si l'épaisseur du film est supérieure à la rugosité de la tige, les résultats numériques qu'on a obtenus sont en bonne corrélation avecles résultats expérimentaux. Dans le cas contraire, le modèle doit être amélioré. Cette amélioration a été entreprise de manière originale. En effet, la théorie inverse est appliquée à la distribution de pression statique du contact obtenue à partir de la simulation par éléments finis de l'assemblage d'un joint rugueux et d'un arbre lisse. La rugosité moyenne (Ra) de la surface dujoint en contact avec la tige a été choisie égale à la rugosité moyenne mesurée du joint étudié. Les résultats ainsi obtenus améliorent sensiblement la corrélation avec les mesures eThis work is a contribution to the study of reciprocating seals behavior. A numerical model, based on the inverse hydrodynamic lubrication theory, is developed to predict their performances. The main contribution consists in the treatment of the hydrodynamic effects in the entry region of contact. The numerical results are validated by comparison with experimentalones, obtained on an original experimental device, design and conceived in the laboratory INOE 2000 IHP of Bucharest. This bench reproduces actual operating conditions of a hydraulic seal and measures the friction force at constant pressure and speed. The comparison of experimental and numerical results was carried out for a "U" type rod seal at different operating pressuresvarying from 4 MPa up to 20 MPa and for two reciprocating speeds. Initially, we idealized the problem by assuming that the surfaces in contact are smooth. The numerical results obtained are in good correlation with experimental ones if the film thickness is greater than the rod roughness. Otherwise, the model must be improved. This improvement was undertaken in an original way. The inverse lubrication theory is applied to the dry frictionless contact pressure distribution, obtained from a FEM simulation of a rough seal and a smooth rod assembly. The average roughness (Ra) of the seal surface in contact with the rod is chosen equal to the measured average roughness of the studied seal. The results obtained significantly improve the correlationwith experimental measurements. The roughness distribution on the entry region of contact appears to have an important influence on the numerical results.POITIERS-SCD-Bib. électronique (861949901) / SudocSudocFranceF

Impact of safety-related dose reductions or discontinuations on sustained virologic response in HCV-infected patients: Results from the GUARD-C Cohort

BACKGROUND: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. METHODS: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0-9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively. RESULTS: SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced 651 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with 651 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not 655. CONCLUSIONS: In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin

Pseudorotaxanes and Rotaxanes Formed by Viologen Derivatives

Dibenzyl-4,4-bipyridinium (BIPY2+) bis(hexafluorophosphate) and three of its derivatives – disubstituted at the para positions of the benzyl groups with CO2Me, F, and Me in turn – have been shown to form 1:1 complexes that are [2]pseudorotaxanes with dibenzo[24]crown-8 (DB24C8), benzometaphenylene[25]crown-8 (BMP25C8), and dipyrido[24]crown-8 (DP24C8) in CD3CN solution by 1H NMR spectroscopy and in one case in the solid state by X-ray crystallography. Binding constants (Ka) for all of these 1:1 complexes, which were determined both (1) by isothermal titration calorimetry in MeCN solution and (2) by the 1H NMR spectroscopic single-point method in CD3CN solution, were found to be, on the average, an order of magnitude less than the Ka values obtained for DB24C8 and DP24C8 with dibenzylammonium (DBA+) hexafluorophosphate and three of its derivatives, also disubstituted at the para positions of the benzyl groups with CO2Me, F and Me. In the case of BMP25C8, however, the Ka values with both categories (BIPY2+ and DBA+) of guests are much of a muchness, being both small and error prone. The equilibrium thermodynamics for these small libraries of [2]pseudorotaxanes indicate that the best bistable [2]rotaxanes incorporating both DBA+ and BIPY2+ recognition sites are going to involve ester functions in their dumbbell components and will employ DP24C8 or, failing that, DB24C8 as the ring component. The BIPY2+ threads also directed the templated assembly of [2]rotaxanes incorporating the crown ethers (DB24C8, DP24C8, and BMP25C8) and triphenylphosphonium stoppers using the threading followed by stoppering approach. The rotaxanes were characterized in solution by 1H NMR spectroscopy, and in one case, in the solid state by X-ray crystallography

DATA MINING. CONCEPTS AND APPLICATIONS IN BANKING SECTOR

The concept of banking refers to the multitude of services and products that commercial banks offer to clients and include besides transactional accounts both passive and active products. Due to the increased competitiveness in banking, the relationship between the bank and the client has become an essential factor for the strategy in order to increase customer satisfaction. Currently the banking system is able to store impressive amounts of data that they collect daily, from customer data and transaction details to data on their transactional or risk profile. The process through which large amounts of data are analyzed, extracted, identified and the information obtained using mathematical and statistical models are interpreted is known as data mining. The discovery of knowledge from data involves identifying some models, some patterns with which certain events or possible risks are anticipated. This process helps banks to develop strategies in areas such as customer retention and loyalty, customer satisfaction, fraud detection and prevention, risk management, money laundering prevention. The aim of this paper is to present the concept of data mining and the concept of data discovery (KDD), but also the impact and important use of data mining techniques in the banking sector. This paper explores and reviews various data mining techniques that are applied in the banking sector but also provides insight into how these techniques are used in different areas to make decision-making easier and more efficient

EVOLUTION OF CUSTOMERS’ SEGMENTATION TECHNIQUES IN RETAIL BANKING

In the context of a highly competitive market influenced by legislative changes, the technology evolution and the changes of customer’s behavior, traditional banks must be able to provide the services and products expected by customers. The most important method in retail banking by which a bank can interact with as many customers as possible to ensure satisfaction and loyalty is the notion of customers’ segmentation. The current situation from the perspective of customers’ expectations will be brought to your attention, as well as the future situation from the perspective of legislative changes and which are the main variables and techniques that allow us a relevant customers’ segmentation in this context. The challenges and opportunities of the Directive PDS2 (Payment Service Directive) [7] will be analyzed, which together with the results of a study carried out by Ernst & Young "The relevance of the challenge: what retail banks must do to remain in the game" [5], make me say that now, more than ever, commercial banks must pay special attention to customer‘ segmentation. The objective of this paper is to present the evolution of the customers’ segmentation process starting from the 50’s – 60’s, when the first segmentation techniques appeared, until now, when because of the large quantities of data, there are used increasingly advanced techniques for extracting and interpreting data