bluuebunny/crossref_metadata_2025_split huggingface dataset:
Passengers Comfort Perception and Demands on Railway Vehicles: A Review
Authors: Filipa Pinheiro da Silva Patrícia , Mendes Joaquim 
Published: June 2020

Trains are becoming a popular way of transportation driven by comfort and ecology reasons. Latest statistics showed an increasing of 40% on the number of passengers in the last decade. The development of new high-speed trains promoted an evolution on the coaches interiors, as to make railway transportation more attractive. To cope this objective, new requirements were set, namely high levels of comfort and safety. In complement, multiple long-term ride comfort evaluation methods have been developed. The aim of this work is to present a review on the passengers’ comfort perception in railway vehicles. The standards ISO 2631, EN 12299 and the Sperling’s method are the most used ones. They refer several factors, as the vibration (level, frequency and duration), temperature, noise and area of the train per capita. Additionally, the perception of reduced accidents delayed the studies of passive security. Therefore, recent works focus on reducing the consequences of the second impact in case of accident and minimize the biomechanics injury criterion, through new interiors design layouts.
Keywords: Railway vehicles, Passengers comfort, Posture, Ride evaluation, Passive safety
Model to Estimate the Project Outcome's Likelihood Based on Social Networks Analysis
Authors: Abreu António 
Published: June 2020

One of the Key Challenges in the area of Project Management, is definitely, how to set up the best Project Team, regarding several key areas, such as; team experience, flexibility, engagement, know-how, and intra and cross-collaboration, so that Project Success Outcome can be achieved. Such best Project Team is definitely very difficult, if not extremely hard to define, especially when it comes to intra and cross-collaboration matters, where in projects environment, implies an extreme dynamic interaction between project people, throughout all the phases of a project lifecycle. Forecasting, to the possible extent, how that people dynamic’s interaction is a critical factor that can contribute to dictate how a project outcome will look like, is becoming a major concern for Risk Management, in Project Management. In this line of thought, the present work aims to further contribute to this particular area of Risk Management, in Project Management, by exploring a new analysis approach, where it points out its focus towards project People, and how the dynamic interaction of project people, that delivers a project, across its lifecycle, influences or not, a certain project outcome type (failure or success). To provide answer to this question, a heuristic model based on three scientific field pillars (Project Management, Risk Management, and Social Network Analysis Theory), is proposed in this work, which aims to identify a set of critical factors, regarding hoe people dynamically interact across the different phases of a project lifecycle, that are to be associated with project success, and project failure outcome.
Keywords: Project management, Risk management, Social networks analysis
Prediction of Pollutants Emissions in a CFM56-3 Combustor, Using Large Eddy Simulation
Authors: Ascensão Costa Morão Inês Isabel , Ribeiro Proença Brojo Francisco Miguel 
Published: June 2020

In the present work a CFD simulation was performed using a CFM56-3 combustor. It was intended to simulate the combustion and emission of pollutants (CO2, CO, UHC and NOx) from the different jet fuels ( Jet A, Jet B and TS-1), when burning these through ICAO’s LTO cycle. Being this a continuity study, the CAD model of CFM56-3 made by Oliveira [5] was used. The mesh was constructed with HELYX-OS software and the numerical study was made using the commercial software ANSYS Fluent16.2. It can be concluded, amongst all the fuels simulated that increasing the power produces higher NOx. There was also an erratic behaviour in the emissions of UHC and CO results, because an empiric model was used and not a detailed chemical model.
Keywords: Jet Fuels, ANSYS Fluent, Pollutants emissions, ICAO’s LTO cycle, CFM56-3
Theoretical Analysis of Ammonium-perchlorate Based Composite Propellants with RDX Containing Small Size Particles of Beryllium
Authors: de Vasconcelos Figueiredo Paulo Alexandre Rodrigues , Ribeiro Proença Brojo Francisco Miguel 
Published: June 2020

Rocket engines have been developed for at least the last six decades. There is a need to improve the actual solid propellant grain for rocket engines through the addiction of metallic fuels in the mixture as well as the addiction of energetic binders to stabilize the combustion. The rocket industry expects the launchers to be reliable, to be faster, stable and to have longer times of operation for the most possible payload weight (operational envelope). New propellants should have optimized ignition and combustion time rates reducing the possibility of negative oxygen balance thus reducing detonation process. Deflagration process should be optimized for best performance of the rocket. In this evolution, small quantities of explosives have been used in the propellant in order to increase the operational burning time, hence, the specific impulse. Adding metallic fuels such as aluminum, boron or beryllium on double based composite propellants and ammonium perchlorate are expected to increase the propellant density over chemical stability and aging resistance. The study of heterogeneous propellants containing large amounts of fine beryllium and ammonium perchlorate, it is necessary to understand the combustion products so to a proper evaluation of specific impulse, Mach number and mass flow of the mixture. In this study a mixture with nitramides (RDX – Cyclotrimethylene trinitramide) and ammonium perchlorate was analyzed with and without the addiction of small size particles of beryllium using a numerical algorithm. Therefore, this study relates the influence of beryllium in the performance parameters of ammonium perchlorate based composite propellants.
Keywords: Propellant, Rocket engine, RDX, Ammonium perclorate
Induction Motor Thermal Analysis Based on Lumped Parameter Thermal Network
Authors: Cabral Pedro , Adouni Amel 
Published: June 2020

Many industry applications required the use of the induction motors. In such envirenement the electrical machines are facing of many stressed operating conditions. One of the critical creteria which decide the choice of the induction motor is the thermal behaviour under different mode operation. In this paper a study of the thermal behavior of an induction motor is presented. In order to predict the temperature in the different machine components, a model based on the lumped parameter thermal network has been developed. The geometry of the machine and the thermal properties of its various components are used to express the developed model. The joule and the iron losses are considering as the inputs. The proposed model is implemented and tested using MATLAB software. It is a simple model which could predict rapidly the different temperatures.
Keywords: Induction motor, Thermal analysis, Lumped parameters thermal network, Modeling, Heat sources
A Study of the Magnetic Field inside the Discharge Chamber of an Ion Thruster
Authors: Abranches Diogo , Brojo Francisco 
Published: June 2020

One of the characteristics that ion thrusters are known for is its high efficiency. In the process of designing an ion thruster the study of the magnetic field alongside the discharge chamber is crucial to achieve optimal efficiency. This work shows the importance of taking into consideration the materials in the vicinities of the magnets as well as the expected intensity of the magnetitic field inside the thrusters in study. The procedures used to study the magnetic field in the open software used are described in this work. The thruster in study is an oversizing done of a previous one, so the desired results are to obtain the ones obtained for the original engine.
Keywords: Ion thruster, High efficiency, Magnetic field
Analysis of Heat Balance in a Light Steel Frame Residence with Different Insulating Thickness
Authors: Oberderfer Consoli Isabel , Rodrigues andrade Carlos Alberto , Lyzandro Tabalipa Ney 
Published: June 2020

Sustainability and efficiency in buildings are concepts that have been recently growing and developing. Its application in several buildings has become mandatory in many countries around the world. One of the major challenges faced by sustainable buildings is the achievement of satisfactory levels in efficiency terms, without negatively impacting the economics. The residential construction sector has great potential for energy savings and is also where building strategies need to be carefully planned, as they seek to meet the needs of residents not only in the present, but also over time. Residential design must be done thoroughly and must include the analysis of all climate variables involved. In order to verify a residential building envelope behaviour regarding energy and thermal efficiency, this paper intended to evaluate through software Design Builder®, walls and roofs with a rock wool layer, placed in a Light Steel Frame (LSF) house.
Keywords: Insulating materials, Light steel frame, Heat gains, Heat losses
Controlled Deposition of Polyamide Nanofibers Through an Innovative Electrospinning Device
Authors: José Ramos Belino Nuno , Aurélio da Silva Nunes Barata Teresa Raquel 
Published: June 2020

Electrospinning is a straightforward, cheap and unique method to produce novel fibers with diameter in the range of 100 nm and even less. Those nanofibers have a wide variety of applications such as: filters, membranes, composite reinforcement, drug delivery, protective barriers, sensors, wound dressings and tissue-engineered scaffolds where their unique properties contribute to product functionality. However, this process is characterized by a chaotic oscillation of the electrospinning jet which leads to the formation of beads an uneven nanofiber. This research work envisages the development of an apparatus to control the deposition of electrospun nanofibers through the use of a series of charged metal rings and the addition of a secondary power source, which enables a greater control over the polymer jet stream.
Keywords: Nanotechnology, Electrospinning, Nanofibres, Controled deposition, Polyamides
Qualitative Approach for Assessing Runoff Temporal Dependence Through Geometrical Symmetry
Authors: Zazo Del dedo Santiago , Macian-Sorribes Hector , Maria Sena Fael Cristina , Garía-Martín Ana-María , Molina Jose-Luis , Pulido-Velazquez Manuel P 
Published: June 2020

Currently, noticeable changes in traditional hydrological patterns are being observed on the short and medium-term. These modifications are adding a growing variability on water resources behaviour, especially evident in its availability. Consequently, for a better understanding/knowledge of temporal alterations, it is crucial to develop new analytical strategies which are capable of capturing these modifications on its temporal behaviour. This challenge is here addressed via a purely stochastic methodology on annual runoff time series. This is performed through the propagation of temporal dependence strength over the time, by means of Causality, supported by Causal Reasoning (Bayes’ theorem), via the relative percentage of runoff change that a time-step produces on the following ones. The result is a dependence mitigation graph, whose analysis of its symmetry provides an innovative qualitative approach to assess time-dependency from a dynamic and continuous perspective against the classical, static and punctual result that a correlogram offers. This was evaluated/applied to four Spanish unregulated river sub-basins; firstly on two Douro/Duero River Basin exemplary case studies (the largest river basin at Iberian Peninsula) with a clearly opposite temporal behaviour, and subsequently applied to two watersheds belonging to Jucar River Basin (Iberian Peninsula Mediterranean side), characterised by suffering regular drought conditions.
Keywords: Causal reasoning, Theorem of Bayes, Temporal dependence propagation, Runoff time series, Water resources management
Aborto habitual. Tratamiento con gonadotropina coriónica humana
Authors: Cifuentes B. Rodrigo , Gómez Gustavo 
Published: June 2020

El aborto espontáneo ocupa el primer lugar entre las causas de fracaso de la gestación. Dentro de este grupo de mujeres se encuentran las pacientes abortadoras habituales por deficiencia del cuerpo lúteo, para quienes se carecía de una terapia efectiva hasta la fecha. Intentos previos para corregir la deficiencia endógena de progesterona administrando por vía exógena esta hormona, no habían sido exitosos. En el presente trabajo se intenta corregir esa deficiencia por medio de gonadotropina coriónica l. M ., la cual provocará la liberación endógena de progesterona. Es así como se seleccionaron dos grupos: uno constituido por 13 embarazadas normales y el segundo por 13 embarazadas con antecedente de 3 o más abortos espontáneos y sin patología detectable. Las pacientes con aborto habitual tuvieron niveles bajos de progestinas plasmáticas al compararlos con las embarazadas normales. Sin embargo, después de administrar gonadotropina coriónica humana a las pacientes abartadoras habituales, los niveles de progestinas se hicieron sensiblemente iguales en ambos grupos y las 26 pacientes finalizaron exitosamente su gestación.Sobre la base de los anteriores resultados se sugiere la administración periódica de cantidades conocidas de gonadotropina coriónica humana en la prevención del aborto en pacientes abortadoras habituales, por deficiencia de progesterona.
Estudio de la pareja estéril
Authors: Sánchez Escoba Fabio , Garcia Gómez Jairo E. , Mejia Restrepo Jorge Mario , De los Ríos Osorio Jesús , Mejía William 
Published: June 2020

Durante las últimas décadas, y a raíz de los adelantos en el área de la Reproducción Humana, le ha correspondido al campo de la esterilidad uno de los mayores progresos: es por ello que la Asociación Antioqueña de Obstetricia y Ginecología ha acogido con beneplácito la elección que se le ha hecho para la presentación de este relato.
Efecto de los senósidos A y B sobre el peristaltismo intestinal durante el puerperio
Authors: Velasco-Chiriboga A. , Perdomo M. A. 
Published: June 2020

Se estudiaron 2 grupos de pacientes sometidas a tratamiento con senósidos A y B para combatir el estreñimiento crónico y el estreñimiento funcional del puerperio. Un grupo de pacientes que tuvieron parto espontáneo y no recibieron ningún tipo de anestesia, se trataron con 2 tabletas de Senokot el primer día, repitiendo el tratamiento al día siguiente. El 70% de pacientes evacuaron dentro de las primeras 20 horas del tratamiento. En otro grupo de 20 pacientes, que se sometieron a operación cesárea, el tratamiento fue eficaz en el 90%. Se consideró el tratamiento como eficaz, fácil de administrar y carente de efectos colaterales: por tanto de gran utilidad en la práctica obstétrica.
Determinación de los valores de densidad óptica a 650nm
Authors: Salazar Galindo Juan Alvaro , Velasco Chiriboga Alvaro , Pacheco Consuegra Carlos Julio , Guzmán Niño Armando 
Published: June 2020

En 84 muestras de líquido amniótico se realizaron lecturas espectrofotométricas diferentes longitudes de onda y se midió la concentración de algunos de los componentes del líquido. Se observa una variación definida en la densidad óptica con la edad de embarazo que permite utilizar esta variable en la predicción del tiempo de gestación, obteniendo la mejor correlación para los 650 nm. Mediante análisis estadístico computarizado se busca la manera de deducir una edad de gestación conocida la densidad óptica, concluyendo la fórmula de mejor probabilidad predictiva.
Radioinmunoanálisis de gonadotropina coriónica: sus valores en embarazos normales y anormales
Authors: Guzmán Miguel , De Estrada Ruth , Tafurt Carlos , Murillo Carmenza , Montenegro María Cristina , Moreno María Consuelo 
Published: June 2020

Se determinaron los valores de gonadotropina coriónica en suero de 10 mujeres con embarazos normales, en muestras tomadas cada 15 días a partir de la semana 30. Los valores obtenidos fueron: semana 30:19.411.lmUl/ml, semana 32:40.635mUl/ml, semana 34: 52, 622mUl/ml, semana 36:62,683mUl/ml, semana 38:37,096mUl/ml. Se estudiaron, igualmente, 7 casos de embarazos molares en los cuales se hallaron niveles previos a la evacuación de la mola del orden de 1.000.000mUl/ml. Se siguió el descenso de la gonadotropina después de la evacuación, hasta llegar, en algunos casos, a valores muy bajos. La gonadotropina coriónica se determinó por un método de radioinmunoanálisis, con una sensibilidad de 9.8mUl/ml en 200μ1 de muestra, estandarizado en nuestro laboratorio. La gonadotropina coriónica humana (hCG) es una hormona glicoprotéica con un peso molecular de 40.000; dado que es secretada por la placenta solo puede detectarse, normalmente, durante el embarazo, incluso a partir del sexto día después de la concepción. También es elaborada por todos los tipos de tejido trofoblástico: molas hidatiformes, corioadenoma destructivo y coriocarcimomas. Fue descubierta en 1927, en orina de mujer embarazada por Aschheim y Zondek (1), quienes establecieron la primera prueba biológica para su detección utilizando como parámetro la respuesta del ovario de ratón prepuberal (2). Posteriormente, Galli-Mainini (3) desarrolló un ensayo simplificado usando sapos machos. En 1960, Brody y Carlstrom (4) prepararon el primer suero anti-hCG y elaboraron una prueba de fijación de complemento para la detección de esta hormona. Bermes (5) describió, en 1969, una prueba de aglutinación directa para el diagnóstico del embarazo. Los ensayos anteriores permiten detectar hasta 500mUl/ml. Con el advenimiento del radioinmunoanálisis de hCG (6) se han logrado límites de detección de 5mUl/ml en 200μ1 de muestra; esta alta sensibilidad permite el diagnóstico precoz del embarazo, aun antes de la primera falla menstrual y el control del tratamiento de las enfermedades trofoblásticas. En el presente trabajo se determinaron los valores normales de hCG a partir de la semana 30 de gestación. Además, se estudiaron algunas pacientes con enfermedad trofoblástica antes y después del tratamiento, utilizando un método de radioinmunoanálisis con segundo anti-suero en fase sólida, desarrollado en nuestro laboratorio.
Hemorragias de la segunda mitad de la gestación
Authors: Blanco Martínez Benjamín , Pérez Pérez Donaldo , Cabrales A. Jorge , Meneses Fernando 
Published: June 2020

En el Departamento de Obstetricia y Ginecología de la Facultad de Medicina de Cartagena, se estudiaron 186 casos de hemorragias de la segunda mitad de la gestación. Los casos fueron seleccionados de 25.286 Historias Clínicas, correspondientes a los años 1976, 1977 y 1978, de la Clínica de Maternidad Rafael Calvo C. y el Hospital Universitario de Cartagena. Anotamos que aproximadamente 9 de cada 1000 embarazadas, en la segunda mitad de la gestación, padecen hemorragias. Clasificadas estas hemorragias según entidades, resultaron para los 3 años, 91 pacientes con Placenta Previa, el mismo número con D.P.P.N.I. y 4 Rupturas Uterinas. La edad promedio de las pacientes con Placenta Previa fue de 29.1 años; para las de D.P.P.N.I. fue de 29.6. La paridad promedio para la Placenta Previa fue de 3.8 partos, para el D.P.P.N.l. fue de 4. En las nulíparas el D.P.P.N.I'* es 3 veces más frecuente que la Placenta Previa. La Placenta Previa y el D.P.P.N.I. se presentaron con marcada frecuencia desde las 34 y más semanas de embarazo. Los casos de Rupturas Uterinas, todos, fueron en embarazos a término.El motivo de consulta predominante en la Placenta Previa, fue el sangrado indoloro (81,3%). El sangrado con dolor predominó en el D.P.P.N.I. /59.3%) y el dolor en la Ruptura Uterina (75%).La hipertonía uterina - estuvo presente en el D.P.P.N.I., con 42 %. La situación trasversa del feto, la cesárea anterior y el manejo por empírica se asociaron con la ruptura uterina en 75%.Las complicaciones maternas predominaron en el D.P.P.N.I., con 79%. Sobresale el Utero de Couvelaire (42.2 %) y la C.I.D (13.5%). El tipo de parto que predominó, fue la Cesárea segmentaria transperitoneal, con 84.9% y fue seguido por el parto vaginal espontáneo con 10.7% El 60% de pacientes fue manejado solamente con líquidos y electrolitos; además de otras medidas generales especiales. El 25% recibió corticoides sangre total. El uso de la Heparina fue exclusivo para el D.P.P.N.I en 25 casos (25.5%). De éstos, 21 (84 %) evolucionario satisfactoriamente y 4 (16 %) murieron. La mortalidad fetal fue de 57 casos (30.6%). De éste, corresponde a la placenta previa 4.9%, al D.P.P.N.I., 23.5% y a la Ruptura Uterina, 2.2%. Analizada esta mortalidad separadamente para cada entidad, según número de casos, corresponde a Placenta Previa 9.9%, al D.P.P.N.I., 48.4%y a la Ruptura Uterina 100 %. El 61% de los fetos fueron mortinatos desde el ingreso; 33.3% tenía sufrimiento y 1.8% estaba normal. La mortalidad materna exclusiva del D.P.P.N.I. fue de 8 casos (8.8 %). Para el número total de casos (186) esta mortalidad , corresponde a 4.3%.
DEVELOPMENT OF BIOLOGICAL ASSESSMENT BASED ON STUDENT CRITICAL THINKING SKILLS: a case study in eleventh grade at MAN 2 Palembang
Authors: Aseptianova Aseptianova , Nawawi Sulton , Astia Resti Maya 
Published: June 2020

This study aims to determine the characteristics and feasibility of biology assessment based on critical thinking skills. This research is a research and development that adapts to the McIntire Miller development model. The sample used in the first trial was 80 students, and in the second trial were 76 students. Data collection techniques using questionnaire sheets, questionnaire sheets, interview sheets, test instruments in the form of essay questions of biology grade XI based on critical thinking from Facione with indicators: interpretation, analysis, evaluation, explanation, conclusions, and self-regulation. Techniques of data analysis using qualitative analysis and quantitative analysis. The results of this study were in the form of a biology assessment based on critical thinking skills in the form of essays in odd semester XI material and from the results of the 1st and 2nd trials totaling 24 items. The content validity of biology assessment based on critical thinking skills is qualified to very high. The construct validity the items are 28 questions valid (1st trial) with reliability value is 0.875. Furthermore, 24 questions are valid (2nd trial) with reliability value is 0.764. The results of the level of difficulty test are 0.332 (1st trial) and 0.537 (2nd Trial). The value of discriminating power is 1,541 (1st trial) and 2,021 (2nd trial). The data shows that the items can be used to measure students' critical thinking skills. We can involve the mental processes of pupils by the test based on critical thinking skills.