Assessment and exploitation of the minimum current harmonic distortion under overmodulation in five-phase induction motor drives

This paper compares the most prominent overmodulation (OVM) techniques for five-phase induction motor drives with respect to the minimum current distortion (MCD) achievable. To attain a benchmark of the latter, two MCD OVM approaches are devised. Contrarily to previous strategies aimed at voltage distortion reduction/minimization, these MCD methods are focused on minimizing the harmonic stator copper loss (HSCL), thus minimizing the current total harmonic distortion (THD). One of these MCD strategies minimizes the HSCL while injecting only x–y harmonics. The other MCD method exploits α–β harmonic injection to further decrease the HSCL and to cover the whole OVM region. Moreover, the dual-mode OVM, which is one of the three-phase methods with the lowest distortion, is extended here for five-phase drives. The findings provide insight into how close the OVM methods are to the benchmark imposed by the MCD strategies. Notably, these MCD techniques yield a significant reduction of current THD, HSCL and peak current, especially for machines with negligible thirdorder space harmonic. The average switching losses are also decreased. Indications for real-time implementation of the MCD solutions are also givenAgencia Estatal de Investigación | Ref. PID2019-105612RB-I00Xunta de Galicia | Ref. ED431F 2020/07Xunta de Galicia | Ref. GPC-ED431B 2020/03Agencia Estatal de Investigación | Ref. RYC2018-024407-

Quality of frozen coipo meat

Para establecer el lapso de aptitud de la carne de nutria conservada por congelación a -18 ºC, se trabajó con los cuartos posteriores de 20 animales criados y faenados en la Facultad de Ciencias Agrarias. Las piezas maduras se acondicionaron individualmente en bolsas de polietileno, se congelaron y se almacenaron a -18 ºC. Al comenzar el ensayo se reservaron 3 muestras para suestudio (testigos) y mensualmente y al azar se descongelaron, a 4 ºC, tres piezas. Cada una fue deshuesada, picada y homogeneizada. Los análisis químicos realizados por triplicado fueron: nitrógeno básico volátil (N.B.V.), Índice del ácido tiobarbitúrico (T.B.A.) y reacción colorimétrica de Kreiss. El estudio estadístico consistió en ajustar diversos modelos, probar su validez, analizando los residuos en cada caso y, en base a los coeficientes de determinación ajustados, aplicar el análisis de regresión simple lineal y probar su significancia. Durante la conservación el N.B.V. se incrementa linealmente, sin sup erar el máximo de 30 mg%g de carne establecido en el Código Alimetario Argentino; el T.B.A. aumenta en forma exponencial, presentando una mayor dispersión de los resultados, cuya tabulación se indica en pág. 76. Luego, la carne de nutria almacenada a -18 ºC, comienza a perder su aptitud para el consumo a los 6 meses de almacenamiento por el incremento de la oxidación de los lípidos.The later quarters of 20 animals reared and killed in the Faculty of Science Agrarian, were used in order to establish the aptitude lapse of coipo meat storage by freezing at -1 8°C. T he mature parts, individually conditioned in polietilene bags, were freezing and storage at -18°C. At the beginning of the trial, preserved 3 samples for their study (witness = time 0), and then, monthly and at random, 3 parts were defrosted at 4°C. Each one was boned, minced and homogeniced. The chemical analysis -made by triplicate-were: vo latile b asic n itro gen (N.B.V.), tiobarbituric acid index (T.B.A.), and Kreiss reaction. The statistic study consisted in: to adjust differents models, to prove their validity (analysing the residues in each case and on the basis of the adjusted determination coeffic ients), to apply the lin ear simp le reg ressio n an alysis and to prove its significance. The N.B.V. increase linearly alon g the storag e, no n surpassing the maximum (established in the C.A.A.) of 30 mg%g of meat. The T.B.A. increase in the exponential way with the storage, presenting a greater dispersion of the results, such is indicated in page 74. So, the c oipo meat storag e at -18 °C loses its aptitud e fo r consumption at 6 month by the increase of the lipids oxidation.Fil: Rosa, Medina de Dias. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Tecnología AgroindustrialFil: Mónica, Zimmermann. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Tecnología AgroindustrialFil: Laura, Sánchez. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Tecnología AgroindustrialFil: Alejandro, Cantisani. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Tecnología Agroindustria

Association between perceived social support and induced abortion: A study in maternal health centers in Lima, Peru.

OBJECTIVES: This study aimed to assess the association between perceived social support and induced abortion among young women in Lima, Peru. In addition, prevalence and incidence of induced abortion was estimated. METHODS/PRINCIPAL FINDINGS: A cross-sectional study enrolling women aged 18-25 years from maternal health centers in Southern Lima, Peru, was conducted. Induced abortion was defined as the difference between the total number of pregnancies ended in abortion and the number of spontaneous abortions; whereas perceived social support was assessed using the DUKE-UNC scale. Prevalence and incidence of induced abortion (per 100 person-years risk) was estimated, and the association of interest was evaluated using Poisson regression models with robust variance. A total of 298 women were enrolled, mean age 21.7 (± 2.2) years. Low levels of social support were found in 43.6% (95%CI 38.0%-49.3%), and 17.4% (95%CI: 13.1%- 21.8%) women reported at least one induced abortion. The incidence of induced abortion was 2.37 (95%CI: 1.81-3.11) per 100 person-years risk. The multivariable model showed evidence of the association between low perceived social support and induced abortion (RR = 1.94; 95%CI: 1.14-3.30) after controlling for confounders. CONCLUSIONS: There was evidence of an association between low perceived social support and induced abortion among women aged 18 to 25 years. Incidence of induced abortion was similar or even greater than rates of countries where abortion is legal. Strategies to increase social support and reduce induced abortion rates are needed

Derecho a la indemnizacion por eventos adversos ligados a los cuidados de salud inseguras según el ordenamiento juridico civil Peruano, Lima, 2020.

Los errores médicos son frecuentes tanto en el sistema de salud pública, como privado, a pesar de los esfuerzos por la implementación hospitales o establecimientos de salud idóneos, así como los sistemas de vigilancia de prevención, control de calidad y normas internas como la de bioseguridad específicas provenientes del Ministerio de Salud como entidad rectora del sistema de salud a nivel nacional. Los cuidados que proporcionan en los servicios que provee el Ministerio de Salud (Minsa) y establecimientos privados, consisten en tratar de alcanzar la curación o mitigar problemas de salud del paciente mediante relación jurídica contractual o extracontractual. Motivo por el que nos planteamos el objetivo de efectiva aplicación del derecho a la indemnización por eventos adversos ligados a los cuidados de salud inseguras según ordenamiento jurídico peruano. Siendo complejo sistema de salud en donde intervienen gran número de bienes y servicios, desde administración de medicamentos, proceso de internamiento, equipamiento, infraestructura, material biomédico y asistencia técnica científica de la comunidad sanitaria (profesionales de la salud), independientemente de su relación laboral. La coyuntura actual del sistema sanitario nacional es cada vez más compleja por el desarrollo tecnológico y científico de las ciencias médicas, los mismos favorecen la incidencia y prevalencia de negligencias médicas conocidas como eventos adversos de salud, son resarcibles por daños causados durante los cuidados de salud, para tal efecto carece de legislación específica con énfasis indemnizatorio por responsabilidad civil o administrativa en sistema sanitario, siendo de urgente necesidad de implementar un seguro médico obligatorio, adicionando fondos del Estado para satisfacer las demandas de victimas de eventos adversos. 2 Para logro de objetivos fue necesario el acceso a la información estadística muy valiosa del Hospital San Juan de Lurigancho (HSJL), correspondiente a los años 2017 y 2018, siendo un total de 361 casos de eventos adversos, clasificamos por categoría, leve 46,8 % (169), moderado 52,4% (189), y grave o centinela 0,8%(3). Siendo el de mayor recurrencia la fractura de clavícula del recién nacido durante la atención de parto 24,1%(87), ulceras por presión (UPP) 14,7% (53), caídas de pacientes durante los cuidados de salud 14,4% (52), asfixia neonatal antes o durante la atención del parto 7,8%(28), flebitis en sitios de inserción de catéter venoso 6,6%(24), infecciones de heridas operatorias (IHO) 3,6% (13), otros casos acumulados 25,8%(93). La información de eventos adversos de carácter nacional proporcionados por el Ministerio de Salud y los gobiernos regionales del país, concernientes a los procedimientos médicos quirúrgicos, en área de hospitalización, nos muestran un total de 14 9 126 de eventos adversos, de los cuales el 97,8% (14 823) corresponden a moderados y el 2,8% (3 303) graves. Precisando que 88,5%(131 908) corresponden a procedimientos quirúrgicos, uso de dispositivos médicos, fármacos y otros, seguidos por infecciones intrahospitalarias tales como: infecciones al tracto urinario (ITU), 2,1% (3 193), infecciones de heridas operatorias (IHO) 3,6% (5 333), neumonías intrahospitalarias (NIH) 2,2% (3 223), flebitis en sitios de inserción de catéter venosa periférica 1,8% (2 640), endometritis por parto vaginal y cesárea 1,3% (1923), ulceras por presión (UPP) 0,5% (756), mortalidad 0,1% (83) correspondiente al año 2016 como dato referencial. En el presente trabajo de investigación, demuestra de forma contundente la prevalencia alarmante de los eventos adversos en los últimos dos años (2017 y 2018), motivo por el cual, se propicia el derecho a la indemnización de eventos adversos de salud inseguras según ordenamiento Jurídico civil peruano, por derecho al consumo y otras normas de rango infra y supra constitucionales con énfasis indemnizatorios. 3 Para el presente informe de investigación, se ha tenido en cuenta fuentes de información provenientes del registro de hospitalización del Ministerio de Salud, mediante Oficina de Tecnología de la información. En el ámbito local (HSJL), área de calidad, supervisión de enfermería, epidemiologia, según variables de interés y casos registrados en base de datos del hospital San Juan de Lurigancho, elegido como centro referencial. La deficiencia de gestión del sistema sanitario y legislativa específica de indemnización por eventos adversos de salud, permite su prevalencia e incremento de la morbimortalidad de los usuarios de salud. Conforme al ordenamiento jurídico, son pasibles de imputación por responsabilidad objetiva, contractual o extracontractual, por culpa y negligencia médica, la que se conoce como evento adverso, por inobservancia del deber de cuidado al paciente, durante las actividades terapéuticas. Por cuanto se debe tener muy en cuenta el siguiente pensamiento filosófico “Médico, en cuanto a las enfermedades ten por costumbre lo siguiente: ayudar, o por lo menos, no hacer más daño” Hipócrates

Confirmation of symmetrical distributions of clinical attachment loss and tooth loss in a homogeneous Mexican adult male population

Background/purpose To ascertain whether or not clinical attachment loss and tooth loss are present with similar severity and prevalence across the two sides of the mouth in a homogeneous sample of urban male adults. Materials and methods A cross-sectional study was carried out on 161 policemen (a largely homogeneous group in terms of ethnic background, socioeconomic status, sex, occupation, and medical/dental insurance) in Campeche, Mexico. Periodontal examinations were undertaken using the Florida Probe System in a dental chair by one trained and standardized examiner (kappa ≥ 0.60) to determine clinical attachment loss and tooth loss. We examined six sites in all teeth present in the mouth (a maximum of 168 sites, no third molars). Because of correlated data between observations, McNemar (for tooth loss) and Wilcoxon (for attachment loss) signed-rank tests were used to compare right and left sites within the same patient. Results The mean age was 38.4 ± 11.0 years. The mean number of teeth present was 24.4 ± 4.6; the mean number of periodontal sites/person was 146.7 ± 27.8. All P values were ≥ 0.05 (except for attachment loss in the upper first premolars), suggesting that there were no statistically significant differences between the right and left sides for the frequency of presentation of these two conditions. Conclusion Tooth loss and attachment loss measurements largely resemble each other on both sides of the mouth

Seasonal thermodynamic prediction of the performance of a hybrid solar gas-turbine power plant

[EN] An entirely thermodynamic model is developed for predicting the performance records of a solar hybrid gas turbine power plant with variable irradiance and ambient temperature conditions. The model considers a serial solar hybridization in those periods when solar irradiance is high enough. A combustion chamber allows to maintain an approximately constant inlet temperature in the turbine ensuring a stable power output. The overall plant thermal efficiency is written as a combination of the thermal efficiencies of the involved subsystems and the required heat exchangers. Numerical values of model input parameters are taken from a central tower installation recently developed near Seville, Spain. Real data for irradiance and external temperature are taken in hourly terms. The curves of several variables are obtained for representative days of all seasons: overall plant efficiency, solar subsystem efficiency, solar share, fuel conversion rate, and power output. The fuel consumption assuming natural gas fueling is calculated and the reduction in greenhouse emissions is discussed. The model can be applied to predict the daily and seasonal evolution of the performance of real installations in terms of a reduced set of parameters.MINECO of Spai

Propuesta de mejora en la gestión de producción y desperdicios a través de herramientas de Lean Manufacturing para reducir costos operacionales en una empresa de fabricación tubos de plástico PVC

El autor no autorizó la publicación de la tesis

Compartmental Learning versus Joint Learning in Engineering Education

[EN]Sophomore students from the Chemical Engineering undergraduate Degree at the University of Salamanca are involved in a Mathematics course during the third semester and in an Engineering Thermodynamics course during the fourth one. When they participate in the latter they are already familiar with mathematical software and mathematical concepts about numerical methods, including non-linear equations, interpolation or differential equations. We have focused this study on the way engineering students learn Mathematics and Engineering Thermodynamics. As students use to learn each matter separately and do not associate Mathematics and Physics, they separate each matter into different and independent compartments. We have proposed an experience to increase the interrelationship between different subjects, to promote transversal skills, and to make the subjects closer to real work. The satisfactory results of the experience are exposed in this work. Moreover, we have analyzed the results obtained in both courses during the academic year 2018–2019. We found that there is a relation between both courses and student’s final marks do not depend on the course

Thermodynamic model of a hybrid Brayton thermosolar plant

[EN]We present a thermodynamic model for the prediction of the performance records of a solar hybrid gas turbine power plant. Variable irradiance and ambient temperature conditions are considered. A serial hybridization is modeled with the aim to get an approximately constant turbine inlet temperature, and thus to deliver to the grid a stable power output. The overall thermal efficiency depends on the efficiencies of the involved subsystems and the required heat exchangers in a straightforward analytical way. Numerical values for input parameters are taken from a central tower heliostat field recently developed near Seville, Spain. Real data for irradiance and external temperature are taken in hourly terms. Curves for the evolution of plant efficiencies (solar, gas turbine, fuel conversion efficiency, overall efficiency, etc.) and solar share are presented for representative days of each season. The cases of non-recuperative and recuperative plant configurations are shown. Estimations of the hourly evolution of fuel consumption are simulated as well as savings between the hybrid solar operation model and the pure combustion mode. During summer, fuel saving can reach about 11.5% for a recuperative plant layout. In addition, plant emissions for several configurations are presented