Development of Prognostics Techniques for Surface Defect Growth in Railroad Bearing Rolling Elements

One of the major causes of failure in railroad bearings used in freight service is rolling contact fatigue (RCF). RCF is due to subsurface inclusions which are a result from impurities in the steel that is used to fabricate the bearings. Once the bearings initiate subsurface fatigue cracks, they will then propagate upward and initiate spalling of the rolling surfaces. These spalls will begin small and continuously propagate with operation as this induces additional crack forming and spalling. Studies have indicated that bearing temperature is not a good indicator of spall initiation. In many cases, the temperature of the bearing increases markedly once the spall has propagated across major portions of the raceway. However, vibration signatures can be used to detect spall initiation and can track spall deterioration. No monitoring system technique can indicate the growth rate of a spall nor can it determine the bearing residual useful life. Therefore, the principle objective of this study is to develop reliable prognostic models for spall growth within railroad bearings that are based on actual service life testing rather than theoretical simulations. The data used to develop the models presented in this study have been acquired from laboratory and field testing that initiated in 2010. The growth models in this study are for spalls that initiated on the bearing inner (cone) and outer (cup) rings. Coupling these prognostic models with a vibration-based bearing condition-monitoring algorithm previously developed, will provide the rail industry with an efficient tool that can be used to propose proactive maintenance schedules that will reduce unnecessary and costly train stoppages and delays and will prevent catastrophic derailments

Prognostics Models for Railroad Tapered Roller Bearings with Spall Defects on Inner or Outer Rings

Rolling contact fatigue (RCF) is one of the major causes of failure in railroad bearings used in freight service. Subsurface inclusions resulting from impurities in the steel used to fabricate the bearings initiate subsurface fatigue cracks, which propagate upwards and cause spalling of the rolling surfaces. These spalls start small and propagate as continued operation induces additional crack formation and spalling. Studies have shown that the bearing temperature is not a good indicator of spall initiation. In many instances, the temperature of the bearing increases markedly only when the spall has spread across major portions of the raceway. In contrast, vibration signatures can be used to accurately detect spall initiation within a bearing and can track spall deterioration. No monitoring technique can indicate the growth rate of a spall or determine residual useful life. Hence, the main objective of this study is to develop reliable prognostic models for spall growth within railroad bearings that are based on actual service life testing rather than theoretical simulations. The data used to devise the models presented here were acquired from laboratory and field testing that started in 2010. Growth models are provided for spalls initiating on the bearing inner (cone) and outer (cup) rings. Coupling these prognostic models with a previously developed vibration-based bearing condition monitoring algorithm will provide the rail industry with an efficient tool that can be used to plan proactive maintenance schedules that will mitigate unnecessary and costly train stoppages and delays and will prevent catastrophic derailments

Estimating the Outer Ring Defect Size and Remaining Service Life of Freight Railcar Bearings Using Vibration Signatures

The railroad industry currently utilizes two wayside detection systems to monitor the health of freight railcar bearings in service: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). TADS™ uses wayside microphones to detect and alert the conductor of high-risk defects. Many defective bearings may never be detected by TADS™ since a high-risk defect is a spall which spans more than 90% of a bearing’s raceway, and there are less than 20 systems in operation throughout the United States and Canada. Much like the TADS™, the HBD is a device that sits on the side of the rail-tracks and uses a non-contact infrared sensor to determine the temperature of the train bearings as they roll over the detector. These wayside detectors are reactive in the detection of a defective bearing and require emergency stops in order to replace the wheelset containing the defective bearing. These costly and inefficient train stoppages can be prevented if a proper maintenance schedule can be developed at the onset of a defect initiating within the bearing. This proactive approach would allow for railcars with defective bearings to remain in service operation safely until reaching scheduled maintenance. Driven by the need for a proactive bearing condition monitoring system in the rail industry, the University Transportation Center for Railway Safety (UTCRS) research group at the University of Texas Rio Grande Valley (UTRGV) has been developing an advanced onboard condition monitoring system that can accurately and reliably detect the onset of bearing failure using temperature and vibration signatures of a bearing. This system has been validated through rigorous laboratory testing at UTRGV and field testing at the Transportation Technology Center, Inc. (TTCI) in Pueblo, CO. The work presented here builds on previously published work that demonstrates the use of the advanced onboard condition monitoring system to identify defective bearings as well as the correlations developed for spall growth rates of defective bearing outer rings (cups). Hence, the system uses the root-mean-square (RMS) value of the bearing’s acceleration to assess its health. Once the bearing is determined to have a defective outer ring, the RMS value is then used to estimate the defect size. This estimated size is then used to predict the remaining service life of the bearing. The methodology proposed in this paper can prove to be a useful tool in the development of a proactive and cost-efficient maintenance cycle for railcar owners

Defect Prognostics Models for Spall Growth in Railroad Bearing Rolling Elements

Prevention of railroad bearing failures, which may lead to catastrophic derailments, is a central safety concern. Early detection of railway component defects, specifically bearing spalls, will improve overall system reliability by allowing proactive maintenance cycles rather than costly reactive replacement of failing components. A bearing health monitoring system will provide timely detection of flaws. However, absent a well verified model for defect propagation, detection can only be used to trigger an immediate component replacement. The development of such a model requires that the spall growth process be mapped out by accumulating associated signals generated by various size spalls. The addition of this information to an integrated health monitoring system will minimize operation disruption and maintain maximum accident prevention standards enabling timely and economical replacements of failing components. An earlier study done by the authors focused on bearing outer ring (cup) raceway defects. The developed model predicts that any cup raceway surface defect (i.e. spall) once reaching a critical size (spall area) will grow according to a linear correlation with mileage. The work presented here investigates spall growth within the inner rings (cones) of railroad bearings as a function of mileage. The data for this study were acquired from defective bearings that were run under various load and speed conditions utilizing specialized railroad bearing dynamic test rigs owned by the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV). The experimental process is based on a testing cycle that allows continuous growth of railroad bearing defects until one of two conditions are met; either the defect is allowed to grow to a size that does not jeopardize the safe operation of the test rig, or the change in area of the spall is less than 10% of its previous size prior to the start of testing. The initial spall size is randomly distributed as it depends on the originating defect depth, size, and location on the rolling raceway. Periodic removal and disassembly of the railroad bearings was carried out for inspection and defect size measurement along with detailed documentation. Spalls were measured using optical techniques coupled with digital image analysis, as well as, with a manual coordinate measuring instrument with the resulting field of points manipulated in MatLab™. Castings were made of spalls using low-melting, zero-shrinkage bismuth-based alloys, so that a permanent record of the spall geometry and its growth history can be retained. The main result of this study is a preliminary model for spall growth, which can be coupled with bearing condition monitoring tools that will allow economical and effective scheduling of proactive maintenance cycles that aim to mitigate derailments, and reduce unnecessary train stoppages and associated costly delays on busy railways

Development of Prognostic Techniques for Surface Defect Growth in Railroad Bearing Rolling Elements

Prevention of bearing failures which may lead to catastrophic derailment is a major safety concern for the railroad industry. Advances in bearing condition monitoring hold the promise of early detection of bearing defects, which will improve system reliability by permitting early replacement of failing components. However, to minimize disruption to operations while providing the maximum level of accident prevention that early detection affords, it will be necessary to understand the defect growth process and try to quantify the growth speed to permit economical, non-disruptive replacement of failing components rather than relying on immediate removal upon detection. The study presented here investigates the correlation between the rate of surface defect (i.e. spall) growth per mile of full-load operation and the size of the defects. The data used for this study was acquired from defective bearings that were run under various load and speed conditions utilizing specialized railroad bearing dynamic test rigs operated by the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV). Periodic removal and disassembly of the railroad bearings was carried out for inspection and defect size measurement and documentation. Castings were made of spalls using low-melting, zero shrinkage Bismuth-based alloys so that a permanent record of the full spall geometry could be retained. Spalls were measured using optical techniques coupled with digital image analysis and also with a manual coordinate measuring instrument with the resulting field of points manipulated in MatLab™ and Solidworks™. The spall growth rate in area per mile of full-load operation was determined and, when plotted versus spall area, clear trends emerge. Initial spall size is randomly distributed as it depends on originating defect depth, size, and location on the rolling raceway. The growth of surface spalls is characterized by two growth regimes with an initial slower growth rate which then accelerates when spalls reach a critical size. Scatter is significant but upper and lower bounds for spall growth rates are proposed and the critical dimension for transition to rapid spall growth is estimated. The main result of this study is a preliminary model for spall growth which can be coupled to bearing condition monitoring tools to permit economical scheduling of bearing replacement after the initial detection of spalls

Changes in the protein profile of Habanero pepper (Capsicum chinense J.) somatic embryos during development

Protein profile was studied during the development of Capsicum chinense somatic embryos. The total protein content and profile of polypeptides (by sodium dodecyl sulfate polyacrylamide gel electrophoresis) of somatic embryos at different developmental stages (globular, heart-shaped, torpedo and cotyledonary stages) were analyzed. The protein profile of zygotic embryos included nine exclusive bands with molecular weights of 4.0, 5.2, 8.1, 13.7, 20.9, 23.7, 41, 50 and 69.3 kDa; these bands were not observed in the protein profile of somatic embryos. Coincidently, five of these bands possessed similar molecular weights to those reported for storage proteins in other plant species. Protein content showed a clear decreasing tendency with increasing somatic embryo development. The lowest protein content was detected in somatic embryos at the cotyledonary stage (0.436 µg/mg fresh weight), and the highest content was found in somatic embryos at the globular stage (2.98 µg/mg fresh weight). Total proteins two-dimensional electrophoresis (2-DE) analysis of mature zygotic embryo (prior to the desiccation) and cotyledonal somatic embryo, showed significant differences in the protein profile of both types of embryos. Zygotic embryo showed the proteins expression of isoelectric point between 4 to 7 and 7 to 10, and molecular weights between 25 to 36 KDa, which were not expressed in the cotyledonal somatic embryo. The low protein content during the development of the somatic embryos, particularly at the cotyledonary stage, is a factor that could be related with the low rate of conversion to plantlets and the high frequency of deformed somatic embryos of C. chinense.Key words: Recalcitrance, maturation, germination, conversion

República Dominicana: Posibles efectos de la liberalización comercial en los hogares rurales, a partir de un modelo desagregado para la economía rural, con énfasis en la pobreza, el género y la migración

El objetivo de este estudio es analizar los posibles impactos de la apertura comercial en los hogares rurales dominicanos. El análisis de impactos económicos se realizó utilizando un modelo de equilibrio general aplicado (MEGA) que captura los efectos directos e indirectos de cambios de política comercial en variables críticas que afectan la toma de decisiones en los hogares rurales. Dichas variables incluyeron producción, ingreso, empleo, cambio tecnológico, precios y migración. El análisis realizado concluye que dicha apertura traerá mayores beneficios de lo anticipado a los hogares rurales más vulnerables, siempre y cuando las reducciones en los precios de los productos básicos de consumo que se esperan como resultado de la liberación, lleguen al consumidor final y se acompañen de medidas que estimulen el ajuste productivo hacia actividades de mayor valor agregado.Desarrollo rural, Acuerdos comerciales, Pobreza, Migración y migrantes, Mujeres, acuerdos comerciales, población rural

Desarrollo de competencias a través de un proyecto multidisciplinario

En un esfuerzo conjunto los profesores de las Facultades de Ciencias de la Comunicación y Salud Pública y Nutrición de la Universidad Autónoma de Nuevo León, desarrollamos un proyecto colaborativo en línea, donde los alumnos inscritos en las materias de Desarrollo de Campañas Publicitarias y Posicionamiento de la FCC y Salud Pública y Nutrición de la FaSPyN desarrollaran competencias de trabajo multidisciplinario y aplicación de las tecnologías de información y comunicación, para el diseño de una campaña publicitaria de enfoque social. El fundamento para el presente proyecto ha sido la Visión UANL 2012 en la cual se establece que “las Tecnologías de Información y Comunicación contribuyen a la creación de ambientes para el aprendizaje, entendidos, estos como situaciones educativas centradas en el estudiante, que favorecen el aprendizaje autodirigido y el desarrollo del pensamiento reflexivo y crítico”, así mismo, que el modelo educativo deberá contemplar el rediseño curricular centrado en el aprendizaje, un enfoque transversal de la currícula que incoprpore persepctivas multi, inter y transdisciplinarias y la incorporación del uso de la tecnologías de Información y Comunicación (TIC) en los procesos de enseñanza aprendizaje. De esta manera organizamos el trabajo en 21 equipos multidisciplinarios constituidos por 1 mercadólogo, 1-2 publicistas, 3-4 nutriólogos. Se establecieron 11 temas diferentes tales como: a) Importancia del desayuno, b) Obesidad infantil, c) Actividad física, d) Lectura de etiquetas, etc. Para que los equipos pudieran trabajar en línea, tanto los maestros como los alumnos de Nutrición, recibieron capacitación en el manejo de la plataforma tecnológica Blackboard, no siendo necesario para los alumnos de ciencias de la comunicación ya que ellos se encuentran inscritos en la modalidad en línea. El resultado de este proyecto son 21 campañas publicitarias que incluyen cartel publicitario, spot de radio y comercial de TV, este material fue utilizado por los alumnos de Nutrición durante la visita que realizaron a las escuelas primarias del área metropolitana de Monterrey con motivo de la celebración del día mundial de la alimentación. El proyecto concluyó con la ceremonia de premiación y entrega de reconocimientos tanto para los alumnos, profesores y autoridades que hicieron posible la realización del mismo

TBCRC 019: A phase II trial of nanoparticle albumin-bound paclitaxel with or without the anti-death receptor 5 monoclonal antibody tigatuzumab in patients with triple negative breast cancer

Purpose: Tigatuzumab (TIG), an agonistic anti-DR5 antibody, triggers apoptosis in DR5+ human tumor cells without crosslinking. TIG has strong in vitro/in vivo activity against basal-like breast cancer cells enhanced by chemotherapy agents. This study evaluates activity of TIG and chemotherapy in patients with metastatic triple-negative breast cancer (TNBC). Experimental Design: Randomized 2:1 phase II trial of albumin-bound paclitaxel (nab-PAC) ± TIG in patients with TNBC stratified by prior chemotherapy. Patients received nab-PAC weekly × 3 ± TIG every other week, every 28 days. Primary objective was within-arm objective response rate (ORR). Secondary objectives were safety, progression-free survival (PFS), clinical benefit, and TIG immunogenicity. Metastatic research biopsies were required. Results: Among 64 patients (60 treated; TIG/nab-PAC n = 39 and nab-PAC n = 21), there were 3 complete remissions (CR), 8 partial remissions (PR; 1 almost CR), 11 stable diseases (SD), and 17 progressive diseases (PD) in the TIG/nab-PAC arm (ORR, 28%), and no CRs, 8 PRs, 4 SDs, and 9 PDs in the nab-PAC arm (ORR, 38%). There was a numerical increase in CRs and several patients had prolonged PFS (1,025+, 781, 672, 460, 334) in the TIG/nab-PAC arm. Grade 3 toxicities were 28% and 29%, respectively, with no grade 4–5. Exploratory analysis suggests an association of ROCK1 gene pathway activation with efficacy in the TIG/nab-PAC arm. Conclusions: ORR and PFS were similar in both. Preclinical activity of TIG in basal-like breast cancer and prolonged PFS in few patients in the combination arm support further investigation of anti-DR5 agents. ROCK pathway activation merits further evaluation