Evaluation of applying retaining shield rotor for high-speed interior permanent magnet motors

This paper proposes a novel rotor structure for high-speed interior permanent magnet motors to overcome huge centrifugal forces under high-speed operation. Instead of the conventional axial stacking of silicon-steel laminations, the retaining shield rotor is inter-stacked by high-strength stainless-steel plates to enhance the rotor strength against the huge centrifugal force. Both mechanical characteristics and electromagnetic behaviors of the retaining shield rotor are analyzed using finite-element method in this paper. Prototypes and experimental results are demonstrated to evaluate the performance. The analysis and test results show that the proposed retaining shield rotor could effectively enhance the rotor strength without a significant impact on the electromagnetic performance, while some design constraints should be compromised.

Investigation of skewing effects on the vibration reduction of three-phase switched reluctance motors

Switched reluctance motors (SRMs) are gaining in popularity because of their robustness, low cost, and excellent high-speed characteristics. However, they are known to cause vibration and noise primarily due to the radial pulsating force resulting from their double-saliency structure. This paper investigates the effect of skewing the stator and/or rotor on the vibration reduction of the three-phase SRMs by developing four 12/8-pole SRMs, including a conventional SRM, a skewed rotor-SRM (SR-SRM), a skewed stator-SRM (SS-SRM), and a skewed stator and rotor-SRM (SSR-SRM). The radial force distributed on the stator yoke under different skewing angles is extensively studied by the finite-element method and experimental tests on the four prototypes. The inductance and torque characteristics of the four motors are also compared, and a control strategy by modulating the turn-ON and turn-OFF angles for the SR-SRM and the SS-SRM are also presented. Furthermore, experimental results validate the numerical models and the effectiveness of the skewing in reducing the motor vibration. Test results also suggest that skewing the stator is more effective than skewing the rotor in the SRMs.

A tidal creek water budget: Estimation of groundwater discharge and overland flow using hydrologic modeling in the Southern Everglades

Taylor Slough is one of the natural freshwater contributors to Florida Bay through a network of microtidal creeks crossing the Everglades Mangrove Ecotone Region (EMER). The EMER ecological function is critical since it mediates freshwater and nutrient inputs and controls the water quality in Eastern Florida Bay. Furthermore, this region is vulnerable to changing hydrodynamics and nutrient loadings as a result of upstream freshwater management practices proposed by the Comprehensive Everglades Restoration Program (CERP), currently the largest wetland restoration project in the USA. Despite the hydrological importance of Taylor Slough in the water budget of Florida Bay, there are no fine scale (∼1 km2) hydrodynamic models of this system that can be utilized as a tool to evaluate potential changes in water flow, salinity, and water quality. Taylor River is one of the major creeks draining Taylor Slough freshwater into Florida Bay. We performed a water budget analysis for the Taylor River area, based on long-term hydrologic data (1999–2007) and supplemented by hydrodynamic modeling using a MIKE FLOOD (DHI,http://dhigroup.com/) model to evaluate groundwater and overland water discharges. The seasonal hydrologic characteristics are very distinctive (average Taylor River wet vs. dry season outflow was 6 to 1 during 1999–2006) with a pronounced interannual variability of flow. The water budget shows a net dominance of through flow in the tidal mixing zone, while local precipitation and evapotranspiration play only a secondary role, at least in the wet season. During the dry season, the tidal flood reaches the upstream boundary of the study area during approximately 80 days per year on average. The groundwater field measurements indicate a mostly upwards-oriented leakage, which possibly equals the evapotranspiration term. The model results suggest a high importance of groundwater contribution to the water salinity in the EMER. The model performance is satisfactory during the dry season where surface flow in the area is confined to the Taylor River channel. The model also provided guidance on the importance of capturing the overland flow component, which enters the area as sheet flow during the rainy season. Overall, the modeling approach is suitable to reach better understanding of the water budget in the mangrove region. However, more detailed field data is needed to ascertain model predictions by further calibrating overland flow parameters.

Kinetic modeling of molecular motors: pause model and parameter determination from single-molecule experiments

Single-molecule manipulation experiments of molecular motors provide essential information about the rate and conformational changes of the steps of the reaction located along the manipulation coordinate. This information is not always sufficient to define a particular kinetic cycle. Recent single-molecule experiments with optical tweezers showed that the DNA unwinding activity of a Phi29 DNA polymerase mutant presents a complex pause behavior, which includes short and long pauses. Here we show that different kinetic models, considering different connections between the active and the pause states, can explain the experimental pause behavior. Both the two independent pause model and the two connected pause model are able to describe the pause behavior of a mutated Phi29 DNA polymerase observed in an optical tweezers single-molecule experiment. For the two independent pause model all parameters are fixed by the observed data, while for the more general two connected pause model there is a range of values of the parameters compatible with the observed data (which can be expressed in terms of two of the rates and their force dependencies). This general model includes models with indirect entry and exit to the long-pause state, and also models with cycling in both directions. Additionally, assuming that detailed balance is verified, which forbids cycling, this reduces the ranges of the values of the parameters (which can then be expressed in terms of one rate and its force dependency). The resulting model interpolates between the independent pause model and the indirect entry and exit to the long-pause state model

Agreed-upon procedures report for the Heart of Iowa Regional Transit Agency relating to the Boone County Transportation, Inc. for the years ended June 30, 2014 and June 30, 2015

Agreed-upon procedures report for the Heart of Iowa Regional Transit Agency relating to the Boone County Transportation, Inc. for the years ended June 30, 2014 and June 30, 2015

Comparative performance analysis of drives for induction motors

The asynchronous polyphase induction motor has been the motor of choice in industrial settings for about the past half century because power electronics can be used to control its output behavior. Before that, the dc motor was widely used because of its easy speed and torque controllability. The two main reasons why this might be are its ruggedness and low cost. The induction motor is a rugged machine because it is brushless and has fewer internal parts that need maintenance or replacement. This makes it low cost in comparison to other motors, such as the dc motor. Because of these facts, the induction motor and drive system have been gaining market share in industry and even in alternative applications such as hybrid electric vehicles and electric vehicles. The subject of this thesis is to ascertain various control algorithms’ advantages and disadvantages and give recommendations for their use under certain conditions and in distinct applications. Four drives will be compared as fairly as possible by comparing their parameter sensitivities, dynamic responses, and steady-state errors. Different switching techniques are used to show that the motor drive is separate from the switching scheme; changing the switching scheme produces entirely different responses for each motor drive.

Caso de estudio. International Soap, INC.

Internacional Soap, Inc. es una compañía norteamericana con su Casa Matriz en Nueva York, que cotiza en la Bolsa de Valores de esa ciudad y hace parte de las 50 compañías más grandes del mundo, según el listado publicado por la Revista Fortune. Como resultado de la globalización de la economía, la crisis financiera asiática y la inestabilidad de las economías emergentes, los ingresos y utilidades de la Corporación se han visto afectadas en los últimos dos años, principalmente por la fortaleza del dólar. De ahí que el Comité Ejecutivo facultara al Presidente para reducir los costos de producción en el mundo y de esta forma mejorar la rentabilidad de los accionistas. Después de un prolongado estudio que llevó más de dos años y en el que se involucraron consultores externos como McKinsey y Co y Andersen Consulting, la decisión estaba tomada: se requiere cerrar 30 de las 60 plantas que existen en el mundo para ser competitivos en el mercado actual; es necesario evitar la duplicidad de inversión de activos en las diferentes regiones y, además, es indispensable tomar ventaja del nuevo orden mundial en cuanto a comercio internacional se refiere. Los bloques económicos (Unión Europea, Mercosur, Nafta, etc.) están facilitando el intercambio entre países, por lo que ya no es necesario tener plantas de producción en cada uno de los países en los que se quiere mercadear el producto. Para Suramérica se definió que deberían quedar solamente dos plantas, una en la parte sur para atender Mercosur y otra en la parte norte, para atender los mercados del Pacto Andino, Centroamérica y el Caribe (actualmente existen plantas de producción en Colombia, Perú y Venezuela). El señor Carlos Casanova, Vicepresidente Operativo para América Latina es el encargado de ejecutar esta pesada y difícil decisión.

Bidirectional cargo transport by microtubule-based molecular motors

We have reconstituted a simple in vitro system using only mammalian dynein and mammalian kinesin attached to a single cargo. These cargoes undergo saltatory motion typically seen in vivo, indicating that the motors engage in a tug-of-war. When the complex hits a barrier, the cargo often reverses direction. In some cases, it tries several up-and-back motions, during which time the dynein likely pulls the cargo onto a different protofilament, and is sometimes able to bypass the blockage. This explains why eliminating kinesin or dynein stops motion in both directions in vivo. We also find that mammalian dynein, but not kinesin, often takes backwards steps when under backward force. However, yeast dynein coupled with mammalian kinesin does not display these attributes, as expected.

PM Motors for High Efficiency Applications

PM motors are suitable for nearly all applications, like pumps, elevators, compressors, blowers, extruders, generators, electric vehicles, servodrives, cooling towers, household appliances, etc. This paper will present some applications where the use of PM motors allowed for enhancements in energy efficiency and process quality.

Diseño de gestión de proyectos bajo la guía metodológica del Project Management Institute, INC. - PMI® para la empresa MABEGO S.A.S.

En la actualidad, las buenas prácticas del Project Management Institute, Inc. (PMI®) son utilizadas en muchas organizaciones para la estructuración, ejecución y cierre de diversos proyectos; las buenas prácticas recogidas por este Instituto han servido de base para que las empresas logren conseguir los objetivos estratégicos con una correcta gestión de los programas y proyectos que se vayan a emprender -- El sector de la construcción no es ajeno a la aplicación de estos estándares, más aún cuando el común denominador son los sobrecostos, la prolongación del cronograma y la variación del alcance, que finalmente terminan afectado la rentabilidad de los proyectos y redundan en la rentabilidad de la empresa -- Mabego S.A.S., es una empresa nueva dedicada a la estructuración, ejecución y venta de proyectos inmobiliarios, cuyo centro de operación es la ciudad de Pasto-Departamento de Nariño, el objetivo principal de la empresa es penetrar el mercado inmobiliario local, teniendo como fortalezas la experiencia y conocimiento aportado por los socios -- Con el presente trabajo se analizan los cuarenta y siete (47) procesos dentro de los grupos de inicio, planeación, ejecución, monitoreo y control, además de cierre establecidos en las diez (10) áreas del conocimiento que establece el PMI® en la guía de los fundamentos para la dirección de proyectos (Guía del PMBOK® - Project Management Body of Knowledge) quinta edición; se crea una metodología de acuerdo a las necesidades de la organización; para conseguirlo se analizaron cada uno de los procesos establecidos en el PMI® y como resultado se presenta la estandarización por medio de formatos y procedimientos que ayudan a la empresa a cumplir con los objetivos específicos de cada uno de sus proyectos -- La pertinencia del trabajo radica en la necesidad de la empresa Mabego S.A.S., de formalizar los procedimientos dentro de la misma, esto debido a que se pretende lograr una correcta estructuración, ejecución y liquidación de los proyectos, además, se aplicó una metodología definida con el objetivo de estandarizar los procesos internos y así lograr un posicionamiento en el sector de la construcción por medio del reconocimiento del cliente en la entrega a tiempo y con la calidad propuesta en los documentos de venta del proyecto