Analysis of lateral dynamics of railway vehicles on viaducts with coupled models

The study of lateral dynamics of running trains on bridges is of importance mainly for the safety of the traffic, and may be relevant for laterally compliant bridges. These studies require 3D coupled vehicle-bridge models, and consideration of wheel to rail contact, a phenomenon which is complex and costly to model in detail. We describe here a fully nonlinear coupled model, described in absolute coordinates and incorporated into a commercial finite element framework. Two applications are presented, firstly to a vehicle subject to a strong wind gust traversing a br idge, showing the relevance of the nonlinear wheel-rail contact model as well as the interaction between bridge and vehicle. The second application is to a real viaduct in a high-speed line, with a long continuous deck and tall piers with high lateral compliance. The results show the safety of the traffic as well as the relevance of considering the wind action and the nonlinear response.

Lateral impact sensor for measuring firmness of fruits in an experimental packing line.

Different parameters are used to quantify the maturity of fruits at or near harvest (shape, color, flesh texture and internal composition). Flesh firmness is a critical handling parameter for fruits such as peach, pear and apple. Results of previous studies conducted by different researchers have shown that impact techniques can be used to evaluate firmness of fruits. A prototype impact system for firmness sorting of fruits was developed by Chen and Ruiz-Altisent (Chen et al, 1996). This sensor was mounted and tested successfully on a 3 m section of a commercial conveyor belt (Chen et al, 1998). This is a further development of the on-line impact system for firmness sorting of fruits. The design of the sensor has been improved and it has been mounted on a experimental fruit packing line (Ortiz-Cañavate et al 1999).

Moment transfer and influence of transverse beams in interior waffle flat plate-column connections under lateral loading

This paper addresses two aspects of the behavior of interior reinforced concrete waffle flat plate?column connections under lateral loads: the share of the unbalanced moment between flexure and excentric shear, and the effect of the transverse beams. A non-linear finite element model (benchmark model) was developed and calibrated with the results of quasi-static cyclic tests conducted on a 3/5 scale specimen. First, from this numerical model, the portion cv of the unbalanced moment transferred by the excentricity of shear about the centroid of the critical sections defined by Eurocode 2 (EC-2) and by ACI 318-11 was calculated and compared with the share-out prescribed by these codes. It is found that while the critical section of EC-2 is consistent with the cv provided by this code, in the case of ACI 318-11, the value assigned to cv is far below (about 50% smaller) the actual one obtained with the numerical simulations. Second, from the benchmark model, seven additional models were developed by varying the depth D of the transverse beam over the thickness h of the plate. It was found that the ductility of the connection and the effective width of the plate can respectively be increased up to 50% and 10% by raising D/h to 2 and 1.5.

Characterization of speech from amyotrophic lateral sclerosis by neuromorphic processing

Amyotrophic Lateral Sclerosis is a severe disease, which dramatically reduces the speech communication skills of patients as disease progresses. The present study is devoted to define accurate and objective estimates to characterize the loss of communication skills, to help clinicians and therapists in monitoring disease progression and in deciding on rehabilitation interventions. The methodology proposed is based on the perceptual (neuromorphic)definition of speech dinamics, concentrated in vowel sound in character and duration. We present the results from a longitudinal study carried out in an ALS patient during one year. Discussion addresses future actions.

Distinct and conserved transcriptomic changes during nematode-induced giant cell development in tomato compared with Arabidopsis: a functional role for gene repression

Root-knot nematodes (RKNs) induce giant cells (GCs) from root vascular cells inside the galls. Accompanying molecular changes as a function of infection time and across different species, and their functional impact, are still poorly understood. Thus, the transcriptomes of tomato galls and laser capture microdissected (LCM) GCs over the course of parasitism were compared with those of Arabidopsis, and functional analysis of a repressed gene was performed. Microarray hybridization with RNA from galls and LCM GCs, infection-reproduction tests and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) transcriptional profiles in susceptible and resistant (Mi-1) lines were performed in tomato. Tomato GC-induced genes include some possibly contributing to the epigenetic control of GC identity. GC-repressed genes are conserved between tomato and Arabidopsis, notably those involved in lignin deposition. However, genes related to the regulation of gene expression diverge, suggesting that diverse transcriptional regulators mediate common responses leading to GC formation in different plant species. TPX1, a cell wall peroxidase specifically involved in lignification, was strongly repressed in GCs/galls, but induced in a nearly isogenic Mi-1 resistant line on nematode infection. TPX1 overexpression in susceptible plants hindered nematode reproduction and GC expansion. Time-course and cross-species comparisons of gall and GC transcriptomes provide novel insights pointing to the relevance of gene repression during RKN establishment.

Nonlinear models for lateral dynamics of railway vehicles on bridges subject to wind action

The study of lateral dynamics of running trains on bridges is of importance mainly for the safety of the traffic, and may be relevant for laterally compliant bridges. These studies require threedimensional coupled vehicle-bridge models, wheree consideration of wheel to rail contact is a key aspect. Furthermore, an adequate evaluation of safety of rail traffic requires nonlinear models. A nonlinear coupled model is proposed here for vehicle-structure vertical and lateral dynamics. Vehicles are considered as fully three-dimensional multibody systems including gyroscopic terms and large rotation effects. The bridge structure is modeled by means of finite elements which may be of beam, shell or continuum type and may include geometric or material nonlinearities. The track geometry includes distributed track alignment irregularities. Both subsystems (bridge and vehicles) are described with coordinates in absolute reference frames, as opposed to alternative approaches which describe the multibody system with coordinates relative to the base bridge motion. The wheelrail contact employed is a semi-Hertzian model based on realistic wheel-rail profiles. It allows a detailed geometrical description of the contact patch under each wheel including multiple-point contact, flange contact and uplift. Normal and tangential stresses in each contact are integrated at each time-step to obtain the resultant contact forces. The models have been implemented within an existing finite element analysis software with multibody capabilities, Abaqus (Simulia Ltd., 2010). Further details of the model are presented in Antolín et al. (2012). Representative applications are presented for railway vehicles under lateral wind action on laterally compliant viaducts, showing the relevance of the nonlinear wheel-rail contact model as well as the interaction between bridge and vehicle.

Lateral Dynamic Models for High-Speed Railway Bridges and Vehicles

The analysis of the running safety of railway vehicles on viaducts subject to strong lateral actions such as cross winds requires coupled nonlinear vehicle-bridge interaction models, capable to study extreme events. In this paper original models developed by the authors are described, based on finite elements for the structure, multibody and finite element models for the vehicle, and specially developed interaction elements for the interface between wheel and rail. The models have been implemented within ABAQUS and have full nonlinear capabilities for the structure, the vehicle and the contact interface. An application is developed for the Ulla Viaduct, a 105 m tall arch in the Spanish high-speed railway network. The dynamic analyses allow obtaining critical wind curves, which define the running safety conditions for a given train in terms of speed of circulation and wind speed

Aplicación de la tecnología GPS para la cuantificación del proceso de readaptación de una lesión de ligamento lateral externo de tobillo: estudio de un caso

GPS y readaptación

Optimización de las superestructuras de autobuses y autocares sometidos al vuelco lateral

En la presente tesis, como en todo proceso de optimization, se ha llevado a cabo un análisis previo de los factores determinantes del problema. Para ello, en primer lugar, se ha puesto a punto un proceso teórico-experimental de verificación de la resistencia de las superestructuras de autobuses y autocares sometidas a vuelco lateral. A partir de la definición de dicho proceso, se ha utilizado el mismo para obtener determinados criterios de diseño que permitan mejorar la relación resistencia/peso de cada estructura. Por último, en base a la experiencia adquirida en la elaboración del proceso de verificación, se han planteado posibles enmiendas y aclaraciones que debieran reflejarse en el Reglamento 66. Este desarrollo ha permitido extraer conclusiones relativas a cada uno de los tres aspectos mencionados: proceso de verificación, criterios de diseño y posibles enmiendas, o rectificaciones, aplicables al Rgto

Minimum volume of long liquid bridges between noncoaxial, nonequal diameter circular disks under lateral acceleration

The stability limit of minimum volume and the breaking dynamics of liquid bridges between nonequal, noncoaxial, circular supporting disks subject to a lateral acceleration were experimentally analyzed by working with liquid bridges of very small dimensions. Experimental results are compared with asymptotic theoretical predictions, with the agreement between experimental results and asymptotic ones being satisfactory

Approach to the potential production of giant reed in surplus saline lands of Spain

Growing energy crops on marginal land has been promoted as a way of ensuring that biomass production involves an acceptable and sustainable use of land. Saline and saline-prone agricultural lands represent an opportunity for growing energy crops avoiding the displacement of food production and contributing to restoration of degraded land. Giant reed (Arundo donax L.) is a perennial grass that has been proposed as a promising energy crop for lignocellulosic biomass production while its tolerance to salinity has been proved. In this work, the identification of surplus saline lands that could be irrigated with saline waters for growing tolerant-energy crops (giant reed) in the mainland of Spain and the assessment of the agronomically attainable yield in these limiting growing conditions were undertaken. To this purpose, a GIS analysis was conducted using geodatabases related to saline areas, agro-climatic conditions, irrigation water requirements, agricultural land availability, restrictions regarding the range of electrical conductivity tolerated by the crop, competition with agro-food crops and irrigation water provisions. According to the approach developed, the irrigated and saline agricultural area available and suitable for biomass production from giant reed amounted up to 34 412 ha. The agronomically attainable yield in these limiting conditions was estimated at 12.7 – 22.2 t dm ha−1 yr−1 and the potential production of lignocellulosic biomass, 597 338 t dm yr−1. The methodology followed in this study can be applied to other target regions; it allows the identification of this type of marginal lands, where salinity-tolerant plant species could be grown for bioenergy purposes, avoiding competition with agro-food crops, and where soil restoration measurements should be undertaken.