Fitting isochrones to open cluster photometric data III. Estimating metallicities from UBV photometry

The metallicity is a critical parameter that affects the correct determination fundamental characteristics stellar cluster and has important implications in Galactic and Stellar evolution research. Fewer than 10 % of the 2174 currently catalog open clusters have their metallicity determined in the literature. In this work we present a method for estimating the metallicity of open clusters via non-subjective isochrone fitting using the cross-entropy global optimization algorithm applied to UBV photometric data. The free parameters distance, reddening, age, and metallicity simultaneously determined by the fitting method. The fitting procedure uses weights for the observational data based on the estimation of membership likelihood for each star, which considers the observational magnitude limit, the density profile of stars as a function of radius from the center of the cluster, and the density of stars in multi-dimensional magnitude space. We present results of [Fe/H] for nine well-studied open clusters based on 15 distinct UBV data sets. The [Fe/H] values obtained in the ten cases for which spectroscopic determinations were available in the literature agree, indicating that our method provides a good alternative to determining [Fe/H] by using an objective isochrone fitting. Our results show that the typical precision is about 0.1 dex

Entrepreneurship as a career option: do temporary workers have the competencies, intention and willingness to become entrepreneurs?

This study analyses the entrepreneurial intentions and the willingness of temporary workers to consider entrepreneurship as a career option. Specifically, we analyse the self-perception of entrepreneurial competencies of a group of temporary workers. A total of 184 temporary workers participated in the study. We performed a multiple correspondence analysis (MCA) to identify profiles of entrepreneurial competencies according to temporary workers' entrepreneurial intention and willingness to consider entrepreneurship as a career option. We conclude that temporary workers do not always perceive themselves as having the necessary competencies to choose for entrepreneurship in their occupational paths. The self-perception of different levels of entrepreneurial competencies is also associated with different intentions and willingness to consider entrepreneurship as a career option. Finally, we provide insights for practice, which can be considered as a starting point for activities aiming to develop entrepreneurial competencies at the individual or organisational levels.info:eu-repo/semantics/submittedVersio

Recognizing opportunities across campus: the effects of cognitive training and entrepreneurial passion on the business opportunity prototype

We analyze the effects of the program Cognitive Entrepreneurial Training in Opportunity Recognition on the accurate assessment of prototypical viability of business opportunities. The training integrates the principles of experiential learning and is designed to reach students across campus. We also investigate the moderating role of entrepreneurial passion on opportunity recognition learning. We use a quasi-experimental design with pre-test, post-test in two European universities. The results demonstrate that the training has positive significant effects on the accurate identification of business opportunities' prototypical viability. Intense positive feelings about entrepreneurship moderate the learning process. We provide insights into entrepreneurship education practice across campus.info:eu-repo/semantics/publishedVersio

The Transversarium-Bifurcatus Zone boundary at Rocha (Peral area, East-Central Algarve, Portugal)

This paper represents the first detailed study of the Transversarium-Bifurcatus Zone boundary in the Algarve. The boundary studied in the Peral area is associated with a stratigraphic discontinuity, whose hiatus partially affects the Transversarium-Bifurcatus Zones. A discontinuity was also recognized in the Bifurcatus-Birnammatum Zone boundary, which can be correlated with the traces of a Type II unconformity, which separates cycles 4.3-4.4 in HAQ et al. (1987), present on the South Iberian palaeomargin. An analysis was made of the ecostratigraphic evolution in the interval between the uppermost Transversarium Zone and the lower part of the Bimammatum Zone on the basis of the faunal spectra obtained. We conclude that ammonites are the most tolerant cephalopods to the ecological stress caused by the increase of inflows and the decrease of the shelf's ecospace. Benthic fauna decreased considerably in these conditions. A relatively abundant and diversified fauna ofDichotomoceras is noteworthy among the ammonites collected, as this genus was previously little known in the Algarve

CALCULATION OF PRESSURE DROP IN NARROW ROTATING ANNULAR CLEARANCES

This paper presents a review of correlations used for pressure drop calculation in narrow annular clearances with rotation of inner cylinder. Based on these review, a new general correlation is proposed to calculate pressure drop through such clearances. Results are compared with experimental data for different flow regimes: laminar, laminar with Taylor vortex, smooth and rough turbulent, with good agreement. The main objective is to develop a simple and general correlation that could be used for backflow calculation in twin-screw multiphase pumps. In this kind of pump, the volumetric efficiency is defined mainly by the backflow rate which occurs in the annular clearance between screw and casing. Usually, the backflow is calculated ignoring the influence of shaft rotation over pressure drop and does not consider the several possible flow regimes. Depending on operational conditions, this simplification can lead to significant errors

SUBSEA MULTIPHASE PUMPING SYSTEM X GAS LIFT: AN EXERGO-ECONOMIC COMPARISON

This paper presents a methodology for an exergetic comparison between two artificial lift systems: a gas lift and a twin-screw multiphase pump system, and a standalone offshore platform. A software (Hysys.Process v2.1) was used to simulate an offshore platform with the artificial lift methods and calculate all properties (including exergy) of the material and energy streams. The twin-screw multiphase pump behavior was simulated with a thermodynamic model developed recently (NAKASHIMA (2000) and NAKASHIMA, OLIVEIRA and CAETANO (2002)). The operational conditions of the PETROBRAS 7- MRL-72D-RJS well operating with cited systems were predicted by an internal study conducted in PETROBRAS (BARUZZI et al. (2001a) and partially published in BARUZZI et al. (2001b)). The comparisons cover the range of 2000 to 2020, the same range adopted in the study. Results show that in general the production costs are lower when the multiphase pump is used. The main advantages of this method over the gas lift is the absence of material (gas) recycle and a better energy management

COLD FLOW NUMERICAL ANALYSIS OF GAS MICROTURBINE COMBUSTION CHAMBER THROUGH CFD TOOL

Gas turbines are equipment used mainly in the generation of electric energy. They have as one of their main components the combustion chamber. Therefore, it is relevant to study the characteristics of this component, in order to reach a satisfactory operation. In this context, this paper presents an analysis of a combustion chamber applied to a gas turbine with a cold flow approach using the numerical theoretical method, through the computational fluid dynamics technique. In this experiment, the software Abaqus CFD (computational fluid dynamics) – present in the 3DExperience platform – and the finite volume method are used. The objective was to evaluate the flow, pressure and velocity profiles during the single-phase flow. The gas turbine prototype is configured using a combustion chamber of reverse flow type in order to decrease flow velocity and increase the combustion efficiency. Based on input data obtained from practical experiments, the calculation of the number and Reynolds confirmed – according to the literature of fluid mechanics – the occurrence of a flow classified as turbulent, with chaotic and random motion, what allows defining the ideal point of injection from analysis of velocity plots with stream lines. In addition, a Mach number smaller than 0.3 confirms the theory of having an incompressible flow, in which compressibility effects can be disregarded. The analysis of mass flow rates of the combustion zones made it possible to evaluate maximum differences of 3% between the design data and the one found in the study. To determine the inherent error of the mesh in the CFD study was calculated through the grid conference method, the value found was around 2.68%

Rendimento da extração de óleos essenciais de frutos quiropterocóricos maduros e imaturos.

EVINCI. Resumo 022

Uso de cúpula acetabular tripolar constritiva no tratamento de fratura do colo do fémur em doente com elevado risco de luxação protética.

Introdução A artroplastia da anca é o procedimento mais usado para o tratamento das fraturas traumáticas do colo do fémur com desvio. Todavia, nos idosos, nos doentes com alterações cognitivas/demência, com patologia neuromuscular, com atrofia muscular, entre outros, o risco de luxação protética é uma séria complicação, que importa prevenir. Para além de outros fatores, a via de abordagem e o tipo de artroplastia podem contribuir para minimizar o risco de luxação protética. Neste sentido, as cúpulas acetabulares tripolares constritivas, bem como outros tipos de reconstruções acetabulares, podem encontrar indicação. O objetivo deste poster é mostrar o tipo de endoprótese implantada para o tratamento de uma fratura do colo do fémur, num doente com elevado risco de luxação protética pós-operatória. Material e Métodos Trata-se de um doente do sexo masculino, com 67 anos de idade, que sofreu uma fratura do colo do fémur esquerdo, tipo III segundo a classificação de Gardner. O exame radiográfico mostrou, também, a existência de obliquidade pélvica, associada a displasia acetabular e coxartrose ipsilateral grau II/III segundo a classificação de Tönnis. Clinicamente, o doente apresentava rigidez do joelho esquerdo com deficit de extensão de 35º e pé esquerdo em equino fixo, sequelas de provável paralisia infantil; o seu perfil cognitivo era baixo, compatível com deficiência mental desde a infância, limitando a sua interacção sociofamiliar. Devido ao status osteoarticular e à atrofia muscular da anca e coxa, implantou-se uma prótese total da anca constritiva, por via posterior. A reconstrução acetabular consistiu na aplicação de um anel metálico de suporte acetabular aparafusado e cimentação de uma cúpula tripolar constritiva. No fémur, cimentou-se uma haste autobloqueante com um colo médio. Resultados Não foram registadas complicações no período pós-operatório. O doente mantém seguimento regular em consulta, apresentando-se assintomático, não tendo ocorrido luxação da prótese total da anca. Discussão Embora reconhecendo as complicações ligadas a este tipo de implantes, incluindo conflitos, dissociações e luxações intraprotéticas, as cúpulas tripolares constritivas e não constritivas (dupla mobilidade) têm sido usadas na cirurgia de revisão de instabilidades recorrentes de artroplastias da anca, em casos selecionados. Tanto quanto sabemos, não existem trabalhos publicados que suportem o uso de anéis de reconstrução acetabular e de cúpulas tripolares constritivas no tratamento de fraturas do colo do fémur com desvio, no contexto de uma artroplastia primária em anca displásica. Temos vindo a indicar este tipo de cúpulas em traumatologia, em doentes com grave demência, debilitados, com insuficiência muscular e, também, em casos extremos ASA III-IV, como alternativa à ressecção artroplástica, com incontornáveis benefícios para o doente. Conclusão A cúpula tripolar constritiva pode ser uma das soluções para o tratamento de fraturas do colo do fémur em doentes com elevado risco de luxação protética, relegando para segundo plano a questão da via de abordagem