The use of novel mechanical devices for enhancing the performance of railway vehicles

Following successful implementation of inerters for passive mechanical control in racing cars, this research studies potential innovative solutions for railway vehicle suspensions by bringing the inerter concept to the design of mechatronic systems. The inerter is a kinetic energy storage device which reacts to relative accelerations; together with springs and dampers, it can implement a range of mechanical networks distinguished by their frequency characteristics. This thesis investigates advantages of inerter-based novel devices to simplify the design of active solutions. Most of the research work is devoted to the enhancement of vertical ride quality; integrated active-plus-novel-passive solutions are proposed for the secondary suspensions. These are defined by different active control strategies and passive configurations including inerters. By optimisation of the suspension parameters, a synergy between passive and active configurations is demonstrated for a range of ride quality conditions. The evidence of cooperative work is found in the reduction of the required active forces and suspension travelling. This reveals a potential for reducing the actuator size. Benefits on power requirements and actuator dynamic compensation were also identified. One of the strategies features a nonlinear control law proposed here to compensate for 'sky-hook' damping effects on suspension deflection; this, together with inerter-based devices attains up to 50% in active force reduction for a setting providing 30% of ride quality enhancement. The study is developed from both, an analytical and an engineering perspective. Validation of the results with a more sophisticated model is performed. The lateral stability problem was briefly considered towards the end of the investigation. A potential use of inerter-based devices to replace the static yaw stiffness by dynamic characteristics was identified. This leads to a synergy with 'absolute stiffness', an active stability solution for controlling the wheelset 'hunting' problem, for reducing the creep forces developed during curve negotiation

Patterns of accounting history literature: Movements at the beginning of the 21st century

This paper addresses and updates the challenge made by Carmona [2004] regarding the need to broaden the accounting history literature into periods, settings, and sectors outside those traditionally published in specialist journals. For this purpose, we review three international journals the Accounting Historians Journal; Accounting, Business & Financial History; and Accounting History and two national publications Rivista di Contabilita e Cultura Aziendali (Italy) and De Computis (Spain) over the period 2000-2008. The results show changes in the publishing patterns of accounting history research. We also explore whether non-Anglo-Saxon researchers have widened the settings, periods, and sectors studied from those of Anglo-Saxon researchers, thus altering the traditional focus of accounting history research

El concepto de la utilidad en el diseño de una prueba de comprensión de lectura en la lengua extranjera

Este artículo representa un diagnóstico completo de la fase de diseño de la prueba de comprensión de lectura para ingreso a estudios de posgrado de la Universidad Autónoma del Estado de México. Para realizar el diagnóstico se determinó medir el alcance del instrumento en relación a las cualidades de utilidad de Bachman y Palmer (1996) siendo éstas: confiabilidad, validez de constructo, autenticidad, interactividad, impacto y practicidad. Como la valoración implícita en la medición de utilidad hace referencia al contexto de la evaluación se describió de manera detallada dicho contexto empleando el modelo de Alderson (2000). La conclusión principal que emana de dicho análisis es que la prueba es adecuada para su contexto en cuanto al diseño pero que la operatividad de la misma se beneficiaría del desarrollo de algunas medidas de difusión.Este artículo representa un diagnóstico completo de la fase de diseño de la prueba de comprensión de lectura para ingreso a estudios de posgrado de la Universidad Autónoma del Estado de México. Para realizar el diagnóstico se determinó medir el alcance del instrumento en relación a las cualidades de utilidad de Bachman y Palmer (1996) siendo éstas: confiabilidad, validez de constructo, autenticidad, interactividad, impacto y practicidad. Como la valoración implícita en la medición de utilidad hace referencia al contexto de la evaluación se describió de manera detallada dicho contexto empleando el modelo de Alderson (2000). La conclusión principal que emana de dicho análisis es que la prueba es adecuada para su contexto en cuanto al diseño pero que la operatividad de la misma se beneficiaría del desarrollo de algunas medidas de difusión

Novel mechatronic solutions incorporating inerters for railway vehicle vertical secondary suspensions

This paper discusses the effects of inerter-based passive networks in the design of novel mechatronic solutions for improving the vertical performance of a bogied railway vehicle. Combinations of inerter-based structures and active suspensions comprise distinct novel mechatronic solutions for the vertical secondary suspension of the vehicle. The parameters of the active and passive parts of the overall configuration are optimised so that a synergy arises to enhance the vehicle vertical performance and simplify common mechatronic suspension design conflicts. The study is performed by combining inerter-based suspensions with well-established active control (output-based and model-based) strategies for ride quality enhancement. Also, a novel nonlinear control strategy, here called Adaptive Stiffness, is incorporated for suspension deflection regulation to complement the well-known local implementation of skyhook damping. This would complete a significant set of control strategies to produce general conclusions. The vehicle performance is assessed through the vertical accelerations of the vehicle body as an initial investigation. Attained results show the potential of the inerter concept for innovating mechatronic technologies to achieve substantial improvements in railway vehicle vertical ride quality with reduced actuator force

Desafíos y retos para la sostenibilidad de las MIPYMES del subsector de restaurantes con la llegada del TLC con Estados Unidos

La llegada del TLC con Estados Unidos genera un serie de retos en diversos sectores de la economía. Uno de estos, es el sub sector de restaurantes, el cual genera una gran cantidad de empleos y de ingresos para la economía colombiana. Es por esto, la importancia de generar recomendaciones y sugerencias que nos permitan ser competitivos para así aprovechar este tratado en vez de verse afectado por él.Within the classification of the sector of services, it is important to emphasize the relevance of the Hotels and restaurants sub-sector in Colombia which is one of the most important for the country's economy. In 2010 the highest growth of nominal gross output was in business of sale of food and beverages by 12.7% over education and other services (DANE). It also is part of the branches of economic activity concentrated in 2010 the largest number of employed, being major generators of employment, commerce, restaurants and hotels accounted for 26.6% of the employed (DANE). For these reasons, it is important to generate recommendations for the service sector and especially for restaurants sub-sector in order to ensure that it remains stable even with the arrival of strong American competitors.Centro de Estudios Empresariales para la Perdurabilida

Formalización y el crecimiento económico de las Mypes de confecciones del programa Compras a Myperú de Huancayo – 2017

La Formalización y el Crecimiento Económico de las MYPEs de Confecciones del Programa Compras A MYPErú de Huancayo, fueron las variables estudiadas para tal efecto el objetivo formulado fue determinar la relación que existe entre la formalización y el crecimiento económico de las MYPEs de confecciones del programa compras a MYPErú. El tipo de investigación fue básica, con un nivel de investigación correlacional y el diseño descriptivo correlacional. La muestra estuvo compuesta por 144 empresarios, los datos se recolectaron haciendo uso de la encuesta, que validada por expertos conocedores de las variables de estudio y para la confiabilidad del instrumento se aplicó a un grupo piloto cuyo resultado aplicando el alfa de Cronbach fue aceptable. Los resultados hallados respecto a la variable formalización muestran que un 2.1% señalan que la formalización de las MYPEs de confecciones del programa compras a MYPErú es muy baja, el 2.1% manifestó que es baja, el 17.4% expresaron que es regular, por otra parte, el 62.5% mencionan que es alta, y el 16% indican que es muy alta; respecto a la variable crecimiento económico el 2.8% de encuestados señalan es muy bajo, y bajo el 6.9%, y el 55.6% mencionan que es alto, y muy alto el 14.6%. Se concluye que la relación entre las variables mencionadas es pequeña como consecuencia del coeficiente tau b Kendall, τ = 0.278 con un nivel de significancia del 99%

Relación entre los serotipos de lengua azul y su vector, en Europa y cuenca mediterránea

La Lengua Azul es una enfermedad de distribución mundial que afecta a rumiantes y se transmite a través de la picadura de las hembras del mosquito del Género Culicoides. Tradicionalmente, la enfermedad ha estado ligada a la presencia del mosquito Culicoides imicola, pero estudios recientes apuntan a una posible implicación de otras especies de mosquitos que puedan sobrevivir en regiones más frías. Utilizando un sistema de visualización geográfica ARCGIS 9.2 (ESRI®) se ha podido representar la distribución de las principales especies de Culicoides implicadas en la transmisión de Lengua Azul en Europa y norte de África y compararlo con el mapa de distribución de los serotipos del virus de la Lengua Azul. El análisis de los mapas realizados prueba que Culicoides imicola está relacionado con la transmisión de los serotipos 1, 2, 4, 9 y 16 y que el complejo Obsoletus transmite el serotipo 8 y podría ser capaz de transmitir otros serotipos del virus con los que hasta ahora no ha tenido contacto.Bluetongue (BT) is a worldwide spread disease affecting ruminants, which is transmitted by the biting of female midges from the Genus Culicoides. Traditionally, this disease has been linked with the presence of the midge Culicoides imicola, but, recent studies have suggested the possibility of other midge species being involved in the transmission of Bluetongue in cooler regions. By applying the geographic information system ARCGIS 9.2 (ESRI®), the distribution of the main Culicoides species involved in Blue Tongue transmission in Europe and the North of Africa and the distribution of BT serotypes in the same region has been represented. The analysis of the maps obtained shows that Culicoides imicola is involved in the transmission of Bluetongue serotypes 1, 2, 4, 9 and 16 and the Obsoletus complex could be able to transmit, besides BTV-8, other BT serotypes with which it has never been in contact so far

Passive suspensions for ride quality improvement of two-axle railway vehicles

The aim of this paper is to investigate the possibility of improving the ride quality of a two-axle railway vehicle with a single-stage suspension by means of passive suspensions employing an inerter device. The inerter is a mechanical one-port element that is analogous to a capacitor in electrical circuits. The goal is to improve the ride quality in both the vertical and lateral motions in response to track irregularities. Performance benefits for several simple passive suspension layouts are demonstrated and compared with the conventional scheme. The elastic effects of the damper and inerter device are then taken into consideration for practical purposes. The optimum parameter values of the damper, inerter and the parameters representing the elastic effects provide guidance for mechanical design purposes

The effect of air pollution on children’s health: a comparative study between La Plata and Bahía Blanca, Buenos Aires Province, Argentina

We present the results of a study of outdoor air quality in two comparable regions of Buenos Aires province (Argentina), La Plata and Bahía Blanca, developed jointly by researchers of National University in both cities, and of the Hospital of Bahía Blanca, between 2009 and 2011. Both regions are characterized by a large petrochemical complex and a village with outstanding traffic. In this study, we measure levels of volatile organic compounds (VOCs), particulate matter suspended in air (PM) in air outdoor and affectation of respiratory system in children between 6 and 12 years. Also, analysis of the effect of the air pollution exposure was done thought the calculation of potentially increased life time cancer risk (LCR) in children. In both regions, including three areas: urban, industrial and residential (reference area), 20 VOCs were sampled by passive monitoring (3M 3500), and determined by GC/FID, comprising n-alkanes, cycloalkanes, aromatics, chlorinated compounds, terpenoids and ketones; particulate matter (PM10) was token using a low flow sampler MiniVol TAS, and spirometry were performed, using a portable spirometer. The collected data show higher levels of PM10 in Bahía Blanca, both in the industrial zone and urban areas, industrial area of Bahía Blanca with very bad air quality, associable with a 5% increased in mortality. The levels of total VOCs found in the residential area for both regions are comparable. Spirometry parameters of children living in industrial area evidence respiratory disease respect to urban and residential areas.Fil: Colman Lerner, Jorge Esteban. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Morales, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Aguilar, M.. Universidad Nacional de La Plata. Fundación Ciencias Exactas; ArgentinaFil: Giuliani, Daniela Silvana. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Orte, Marcos Agustín. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ditondo, J.. Hospital Interzonal General de Agudos “Dr. José Penna”; ArgentinaFil: Dodero, Veronica Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Massolo, L.. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Sanchez, Erica Yanina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Matamoros, N.. Universidad Nacional de La Plata. Facultad de Ingenieria; ArgentinaFil: Porta, A.. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentin

High Endemicity of Soil-Transmitted Helminths in a Population Frequently Exposed to Albendazole but No Evidence of Antiparasitic Resistance

Soil-transmitted helminths (STHs) are gastrointestinal parasites widely distributed in tropical and subtropical areas. Mass drug administration (MDA) of benzimidazoles (BZ) is the most recommended for STH control. These drugs have demonstrated limited efficacy against Trichuris trichiura and the long-term use of single-dose BZ has raised concerns of the possible emergence of genetic resistance. The objective of this investigation was to determine whether genetic mutations associated with BZ resistance were present in STH species circulating in an endemic region of Honduras. Methods: A parasitological survey was performed as part of this study, the Kato–Katz technique was used to determine STH prevalence in children of La Hicaca, Honduras. A subgroup of children received anthelminthic treatment in order to recover adult parasite specimens that were analyzed through molecular biology techniques. Genetic regions containing codons 200, 198, and 167 of the β-tubulin gene of Ascaris lumbricoides and Trichuris trichiura were amplified and sequenced. Results: Stool samples were collected from 106 children. The overall STH prevalence was 75.47%, whereby T. trichiura was the most prevalent helminth (56.6%), followed by A. lumbricoides (17%), and hookworms (1.9%). Eighty-five sequences were generated for adjacent regions to codons 167, 198, and 200 of the β-tubulin gene of T. trichiura and A. lumbricoides specimens. The three codons of interest were found to be monomorphic in all the specimens. Conclusion: Although the inability to find single-nucleotide polymorphisms (SNPs) in the small sample analyzed for the present report does not exclude the possibility of their occurrence, these results suggest that, at present, Honduras’s challenges in STH control may not be related to drug resistance but to environmental conditions and/or host factors permitting reinfections.Brock University Library Open Access Publishing Fun