bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phytochemical investigation of the bioactive extracts of the leaves of Ficus cyathistipula Warb.
Authors: El-Sakhawy Fatma , Kassem Hanaa , Abou-Hussein Dina , El-Gayed Sabah , Mostafa Mayy , Ahmed Rania 
Published: April 2016

Abstract
Ethanolic and aqueous leaf extracts of Ficus cyathistipula significantly reduced blood-glucose level, improved triglycerides and cholesterol levels of dyslipidemia in diabetic-rats. They similarly reduced the inflammation of paw-edema and stomach-ulcers in rats. Fractions obtained by successive partition of ethanolic extract were assessed for their cytotoxicity, antioxidant and antimicrobial activities; Petroleum ether fraction was the most cytotoxic (IC50 = 4.43 ± 0.2, 17.3 ± 2.22 and 15.5 ± 3.67 μg/ml on MCF7, HepG2 and HeLa cell lines, respectively). Ethyl acetate fraction was the strongest antioxidant in DPPH assay (IC50 = 100 μg/ml). All samples exhibited low to strong antimicrobial activity. Chemical investigation of leaf extracts led to the isolation of α-amyrin palmitate (1), lupeol acetate (2), taraxerol (3), β-sitosterol (4), protocatechuic acid (5) and 3-O-caffeoyl quinic acid (6) that were identified via spectral and chromatographic analyses. Metabolite profiling was performed via UPLC-PDA-MS and revealed the presence of flavonoid glycosides, phenolic acids, isoflavones, coumarins and fatty acids. Quantitative determination revealed 593 ± 0.5 mg BSE, 348.1 ± 0.09 mg GAE, 238.7 ± 0.5 mg rutin and 9 ± 0.5 g tannins per 100 g d.wt. of leaves. GLC analysis of lipid fraction revealed identification of phytosterols (15.6%), saturated (51.71%) and unsaturated (41.9%) fatty acids. Galactose, glucose, arabinose and glucoronic acid (36.98%, 28.86%, 22.56% and 1.06%, respectively) were identified by HPLC analysis of mucilage-hydrolysate.
X-Ray Imaging Inspection System for Blind Holes in the Intermediate Layer of Printed Circuit Boards with Neural Network Identification
Authors: Lin C.-S. , Chan B.-E. , Huang Y.-C. , Chen H.-T. , Lin Y.-C. 
Published: April 2016

Abstract
This study presented an X-ray imaging inspection system with a backpropagation neural network that could increase the accuracy of defect detection and classification of blind holes in the intermediate layer of printed circuit boards (PCBs). In this system, a multilayer PCB image was obtained from an X-ray camera. The original image was then converted into a binary image with a noise-suppression filter, and the edge-detection method was used to compare the image with a standard sample. Drilling was based on the hole-position's accuracy measurement to obtain the hole flak figure, which was useful for calculating the drilling coordinate error with a backpropagation neural network. The proposed method could determine the information of the PCB edge test holes automatically. The accuracy of the feature extraction was increased by using the proposed module-detection method, together with image processing and the backpropagation networks process.
Monitoring on the Auto-Analyzer System in-Statistical-Control for SO2 in Atmosphere With Top-Down Uncertainty Evaluation
Authors: Wang D. W. , Sun H. R. , Pan Z. Q. , Deng Y. , Liang C. Z. , Feng O. 
Published: April 2016

Abstract
In this paper, the top-down approach (CNAS-GL34: Guidance for Measurement Uncertainty Evaluation Based on Quality Control Data in Environmental Testing, China National Accreditation Service for Conformity Assessment, Beijing, China, 2013) for A type evaluation of empirical model can be applied to qualify the SO2 by using analyzer and primary test method (PTM) (GB/T 27408: Quality Control in Laboratories—Evaluating Validity of Non-Standard Test Method—Practice for a Linear Relationship, Standardization Administration of the People's Republic of China, Beijing, China, 2010), whereupon a large number of real-time data, in multi-sites at different levels, were accumulated under site precision (sR′) in-statistical-control condition (GB/T 27411: Routine Methods for Evaluation and Expression of Measurement Uncertainty in Testing Laboratory, Standardization Administration of the People's Republic of China, Beijing, China, 2012). The data-transformed-system under investigation cannot be considered suspect as none of the Anderson Darling (AD) statistics were failed in acceptance at the 95 % confidence level for the hypothesis of normality and independence. Our survey was originated from the fog-haze over a period of time for SO2 in air, with its boundary of 100 × 10−9∼400 × 10−9. Finally, the top-down approach, based on closeness sum of squares (CSS), gave the reliable and valid evaluation as the expanded uncertainty, U = 8.5 μg/m3, which maximized the combination of the effects on various variances, refrained from the complicated relativity by bottom-up for uncertainty evaluation.
Preparation and Performance Test of Soldered Stators of Ultrasonic Motor
Authors: Li Zhiqiang , Xue Songbai , Ding Qingjun 
Published: April 2016

Abstract
In order to obtain the optimal reflow parameters, a Sn-52In solder was adopted to join a PZT8 piezoelectric ceramic to a copper stator elastic-body, which matched with rosin organic flux. Modal testing was carried out to evaluate the vibration performance of the soldered stators. The results show that when the reflow parameters were 140°C, 115 s, and 100 N pressure, the soldered stators had the best vibration performance. The soldered stators can generate a B09 mode shape which is required by the TRUM-60 ultrasonic motor. Moreover, the coincidence of the two phase modal frequencies of soldered stators can fully meet the requirement of ultrasonic motors and there is no interference frequency near the operating modal frequency (around 40 kHz). With an electrical excitation of 80 Vpp, the amplitude of the soldered stators was 2.5 μm, which can reach the level of vibration of bonded stators with adhesives. Therefore, the soldering process could be expected to solve the problem of aging of the adhesive layer, thereby improving the service life of ultrasonic motors to a certain extent.
Estimation of a Modified Capability Index for Non-Normal Distributions
Authors: Pearn W. L. , Tai Y. T. , Wang H. T. 
Published: April 2016

Abstract
Process capability indices (PCIs), which are very important in quality control have been one of a numerical measure index in manufacturing processes. Index Cpk is the most popular one used in the manufacturing industry. It is applied under the assumption that the processes are normally distributed. In real-world applications, non-normal processes may occur in industries, and the index CNpk has been proposed for non-normal processes in which its exact sampling distribution is mathematically intractable. Quality practitioners commonly use the existing NCPPM (non-conformities in parts per million) table of Cpk to obtain process yields. However, the table could not be applied directly via the value of index CNpk. For the consistency of NCPPM mapping, we propose procedures to obtain the modified index C*Npk and its approximately unbiased estimator C˜*Npk for three non-normal distributions, involving Log-normal, Gamma, and Weibull distributions. The values of modified index C*Npk could be used to inquire the existing popular NCPPM table of Cpk. In addition, four bootstrap methods were used to construct the lower confidence bounds of the index C*Npk, which are useful to the practitioners for making reliable decisions regarding process performance based on process yield.
Experimental Verification of a Module-Integrated Isolated Coupled-Inductor-Based dc–dc Boost-Converter-Fed Micro-Inverter
Authors: Geetha P. , Ravi S. 
Published: April 2016

Abstract
In this paper, a photovoltaic module-integrated coupled inductor-based high-step-up dc–dc converter-fed isolated dc/ac converter is presented. The coupled-inductor-based dc–dc converters offer more advantages over the buck, boost, and cuk converters used in the photovoltaic (PV)-integrated applications. The proposed grid-integrated solar micro-inverter based on the isolated high-step-up dc–dc converter extracts the maximum power generated on the solar panel and it transfers the extracted power to the ac utility system through a voltage source inverter. High-step-up voltage gain, high maximum power point tracking accuracy, and high-energy-conversion efficiency can be obtained with the proposed topology. The design considerations and principle of operation of the proposed isolated high-step-up dc–dc boost-converter-fed micro-inverter are analyzed and discussed. The MATLAB/Simulink simulation and experimental results of the proposed micro-inverter have been presented to validate the performance of the isolated micro-inverter.
Analysis on the Issues in ISO 6892-1 and TENSTAND WP4 Report Based on the Data of Confirm Tests by 21 Laboratories
Authors: Li H. , Zhou X. , Shen J. , Luo D. 
Published: April 2016

Abstract
To better understand and reach consensus on a series of issues around the standard ISO 6892-1 and TENSTAND WP4 report, extensive experiments were conducted using 5 different methods with non-aging high-uniformity tensile reference materials. These tests were performed by 21 laboratories and a number of findings have been observed by analyzing the data collected from these tests. The findings suggested that the two reasons to recommend strain control method cited in TENSTAND WP4 report were not valid as the actual test conditions do not match the conditions in the report. A number of unjustified requirements in ISO 6892-1 were listed in this paper according to the findings. Four requests to update ISO 6892-1 were proposed for consideration.
Marcas discursivas de medicalización en anuncios publicitarios
Authors: Plazas Salamanca Adriana Margarita 
Published: April 2016

<p>El presente artículo expone los elementos de construcción de lafecundación como problema biopolítico. A través de la revisión de los términos <em>control natal </em>y <em>planificación familiar </em>se observan las prácticas de medicalización que responden a políticas y programas de control demográfico. El objetivo reside en describir las marcas discursivas que evidencian las prácticas de medicalización presentes en las pautas publicitarias de la marca Norforms. La medicalización centra su interés en expandir sus acciones de control sobre la vida en el caso particular de los óvulos anticonceptivos, en el que se puede visibilizar la estrategia de creación de la enfermedad social y la promoción del tratamiento a través de las campañas de difusión de la higiene pública. En el artículo se presentan los resultados del análisis de cuatro anuncios publicitarios de la marca Norforms publicadas en revistas que circulaban en Bogotá en 1964, 1972, 1991, 1998. Para el análisis discursivo se recurre a los conceptos de <em>biopolítica </em>y <em>medicalización </em>proporcionados por Michel Foucault a partir de los cuales se describen las dinámicas económicas y políticas de control poblacional.</p>
Un método para determinar un grupo de observaciones influyentes en la SCE al ajustar modelos de rango completo
Authors: Rincón Suárez Luis Fransisco 
Published: April 2016

En este artículo se presenta un método que permite establecer la existencia de un grupo de observaciones influyentes para la SCE al ajustar un modelo lineal de rango completo. En el análisis de residuales se utiliza la estadística Q_i y el criterio se construye usando la distribución de las estadísticas mencionadas bajo el supuesto clásico e_i N(0;\sigma^2) y Cov(e_i,e_j)=0 si ineq j.
Análisis estadístico de la producción de un biocontrolador de la mosca blanca en plantas de frijol bajo invernadero
Authors: Díaz Marco Antonio , Cantor Fernando , Rodríguez Daniel 
Published: April 2016

La mosca blanca de los invernaderos Trialeurodes vaporariorum es una de las plagas agrícolas de mayor importancia en la sabana de Bogotá. Para su manejo se han implementado diferentes estrategias de control, como el uso de enemigos naturales, siendo esta una alternativa ecológica. La avispa parasitoidea Encarsia formosa se ha reconocido como controlador natural de esta plaga y su uso ha sido documentado mundialmente como uno de los casos exitosos de control biológico más reconocidos. En los últimos años la Universidad Militar Nueva Granada ha establecido una cría semi-comercial de este controlador con fines de distribución y venta agrícola en la sabana de Bogotá. Con el fin de optimizar el proceso de producción de la cría, se realizó un análisis estadístico recopilando los datos de producción de los meses de agosto a diciembre del 2010. Se estableció el nivel máximo, mínimo y el promedio de producción a partir de la información recolectada. Posteriormente, se realizó una fase experimental para encontrar la relación entre el área foliar de una planta de frijol atacada y el porcentaje de infestación de la plaga, la preferencia de oviposición de E. formosa en la hoja de frijol infestada con T. vaporariorum y la relación entre el número de avispas usadas en la cría con el número de avispas producidas. Se encontró que no existe una relación entre el área foliar con el número de individuos de la plaga pero sí una preferencia de alimentación hacia la zona central de la hoja. Finalmente se ajustó una regresión polinomial entre la eficiencia de parasitación de la avispa con la población de la misma. Se concluye que para mejorar la producción es necesario liberar una cantidad menor de avispas de las establecidas originalmente.
Un método para determinar observaciones influyentes en la SCE al ajustar modelos de diseños factoriales
Authors: Ubaque Lopez Blanca Cecilia , Rincón Suárez Luis Francisco 
Published: April 2016

En este artículo se presenta la generalización de la estadística Q_i y el criterio para determinar observaciones influyentes para la SCE al ajustar un modelo lineal Y=Xbeta+e de rango incompleto en diseños factoriales. En el análisis de residuales se generaliza la estadística mencionada bajo el supuesto clásico e_i N(0;sigma^2) y Cov(e_i,e_j)=0 si i\neq j).
Una aplicación estadística de los métodos de clasificación en astronomía
Authors: Hortúa Héctor , Zambrano Alex J. 
Published: April 2016

En los últimos años, los avances en astrofísica y cosmología han sido impulsados por grandes y complejos conjuntos de datos, los cuales sólo pueden ser analizados e interpretados con el uso de métodos estadísticos muy refinados. Esto ha llevado a que estas disciplinas se complementen para formar una rama llamada la astroestadística. En este trabajo se da a conocer un método de clasificación estadístico usando modelos de mezclas de Gausianas. Este método se aplicará para encontrar estrellas que pertenecen al cúmulo de las Hyades usando una muestra de 2678 estrellas de la base de datos de Hipparcos. Se realiza una descripción breve de las características del cúmulo y se estudia la evidencia de outliers. Con este método se encuentra que la clasificación arroja tres grupos de los cuales podemos estudiar la pertenencia al cúmulo y se encuentra que la mayoría de estrellas pertenecientes al mismo están de acuerdo con la literatura. También se muestra el diagrama de Hertzsprung-Russell obtenido para el cúmulo, muy importante en estudios de evolución estelar. Finalmente, se analiza un tercer grupo obtenido por el método el cual fue analizado a través de filtros y otros métodos estadísticos para el manejo de outliers y determinar con más precisión la pertenencia de las estrellas en el cúmulo de las Hyades.
Modelos TAR en series de tiempo financieras
Authors: Moreno Edna , Nieto Fabio H. 
Published: April 2016

<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>En este artículo, se evalúa el desempeño de un modelo autorregresivo de umbrales (TAR),en el análisis de series de tiempo financieras. Se utilizan datos del mercado accionario brasilero y norteamericano a fin de ajustar un modelo; además se realiza una comparación con los modelos GARCH vía los momentos condicionales. </span></p></div></div></div>
Una propuesta metodológica para elicitar el vector de parámetros π de la distribución Multinomial
Authors: Flórez Rivera Andrés Felipe , Correa Morales Juan Carlos 
Published: April 2016

<p>Cuando no existe información previa o es muy costosa obtenerla, las distribuciones a priori informativas brindan una opción práctica y “económica” que sirven de base para el inicio de un proyecto o un estudio en particular. En este trabajo presentamos una propuesta metodológica para llevar a cabo un proceso de elicitación que permite extraer el conocimiento de un experto e incorporarlo como una distribución a priori del vector de parámetros de la distribución Multinomial. Aquí presentamos la metodología propuesta acompañada de una ilustración y finalizamos con algunas conclusiones y recomendaciones.</p>
Influence of heat transfer on two-phase flow behavior in onshore oil pipelines
Authors: Romero Oldrich Joel , Saad Hugo Candiá , Pereira Isabela Braga , Romero Mao Ilich 
Published: April 2016

<p>Computational tools for simulation of multiphase flow in oil pipelines are of great importance for the determination of the technical feasibility of the production in oilfields. The present article presents the mathematical and numerical modeling of the oil biphasic flow in a partially submerged onshore pipeline. The biphasic behavior of the heavy oil of 13,2ºAPI is translated by the Dukler correlation. The oil’s viscosity is regarded as dependent on the temperature and on the API density of the oil by means of the Hossain correlation. The pipeline, of 3,600m and 4 inches (10.16cm) in diameter, transports the oil from a collecting station to a storage center and consists of three sections. The first and third sections are above ground and are in contact with the external environment. The intermediate section is sitting on the river bed and is the critical part of the pipeline, once high heat losses are observed. The influence on the type of pipe insulation in the pressure and temperature gradients was analyzed with the aid of commercial 1D software Pipesim®. The results, of this 1D and non-isothermal problem with prescribed outlet pressure, show that the use of isolation when appropriately designed in terms of material quality and thickness is of utmost importance to maintain the heat transfer at low levels, in order to ensure the movement of fluids in long sections without compromising the system operation.</p>
Isotropic damage model and serial/parallel mix theory applied to nonlinear analysis of ferrocement thin walls. Experimental and numerical analysis
Authors: Paredes Jairo A. , Bedoya-Ruiz Daniel Alveiro , Hurtado Gómez Jorge E. 
Published: April 2016

<p>Ferrocement thin walls are the structural elements that comprise the earthquake resistant system of dwellings built with this material. This article presents the results drawn from an experimental campaign carried out over full-scale precast ferrocement thin walls that were assessed under lateral static loading conditions. The tests allowed the identification of structural parameters and the evaluation of the performance of the walls under static loading conditions. Additionally, an isotropic damage model for modelling the mortar was applied, as well as the classic elasto-plastic theory for modelling the meshes and reinforcing bars. The ferrocement is considered as a composite material, thus the serial/parallel mix theory is used for modelling its mechanical behavior. In this work a methodology for the numerical analysis that allows modeling the nonlinear behavior exhibited by ferrocement walls under static loading conditions, as well as their potential use in earthquake resistant design, is proposed.</p>
Design of a 2DOF parallel mechanism to assist therapies for knee rehabilitation
Authors: Chaparro Rico Betsy Dayana Marcela , Castillo Castañeda Eduardo 
Published: April 2016

<p>This paper presents a knee rehabilitation device to reproduce four exercises generally used in the rehabilitation therapies. The device consists of a mechanical structure based on a 2 DOF parallel mechanism, a controller with PIC-SERVO motion control boards, and a GUI that commands the device to reproduce the rehabilitation exercises. The position kinematic analysis of the mechanism is developed as well as its dimensioning synthesis to cover various leg sizes. This work proposes a technological alternative with significant advantages that responds to the global need for improving physical knee rehabilitation process. A prototype was manufactured and its mobility was validated using a mannequin.</p>
Developing Student-teacher’s Instructional Communication Skills through Teaching Practice: the Attitudes of Mentors
Authors: Viršulienė Kristina 
Published: April 2016

The article analysis the attitudes of mentors to the development of student-teacher’s instructional communication skills through teaching practice. The objective of the research was to reveal the opinion of the mentors about the development of student-teacher’s instructional communication. For that purpose observation was carried out in the natural environment. That helped to reveal the peculiarities of students’ instructional communication skills at teaching practice. Semi-structured interview methods were applied to interview the mentors. The data obtained via the Questionnaire for Mentors allowed to assess the student-teachers’ communication skills, and to identify the key factors for theirs’ professional improvement.
The interview data analysis presents mentors’ opinion about the dynamics of the student - teachers’ instructional communication skills at teaching practice, the importance of consultations, student-teachers’ assessment of their instructional skills, needs and possibilities of the skill improvement. It became evident that mentors’ assessment differed according to their work experience. When speaking about students’ assessment, the mentors of considerable experience (more than 5 years of continuous pedagogical work experience) admitted, that they had known students well through observing, communicating, consulting them, when talking to their colleagues they could assess their achievements. While the inexperienced mentors communicated with the student-teachers in a more formal way, they were less prepared to supervise students, help them know themselves and improve their instructional skills.
When considering improvement possibilities of teaching practice, all mentors claimed that student-teacher’s professional skills are being gained only by practicing. The mentors stressed that readiness for pedagogical professional practice is very much dependent on student’s ability to participate, to reflect, on willingness for self-knowledge as well as strong professional determination; results of individual practice and consultations with competent professionals.