Experimental modal analysis of transverse-cracked rails-influence of the cracks on the real track behavior

Domingo, Laura Montalban,Giner, Beatriz Baydal,Martin, Clara Zamorano,Herraiz, Julia I. Real Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.5

Rails are key elements in railway superstructure since these elements receive directly the train load transmitted by the wheels. Simultaneously, rails must provide effective stress transference to the rest of the track elements. This track element often deteriorates as a consequence of the vehicle passing or manufacturing imperfections that cause in rail several defects. Among these rail defects, transverse cracks highlights and are considered a severe pathology because they can suddenly trigger the rail failure. This study is focused on UIC-60 rails with transverse cracks. A 3-D FEM model is developed in ANSYS for the flawless rail in which conditions simulating the crack presence are implemented. To account for the inertia loss of the rail as a consequence of the cracking, a reduction of the bending stiffness of the rail is considered. The numerical models have been calibrated using the first four bending vibration modes in terms of frequencies. These vibration frequencies have been obtained using the Experimental Modal Analysis technique, studying the changes in the modal parameters of the rails induced by the crack and comparing the results obtained by the model with experimental results. Finally, the calibrated and validated models for the single rail have been implemented in a complete railway ballasted track FEM model in order to study the static influence of the cracks on the rail deflection caused by a load passing.

Screening of ‘King’ mandarin (Citrus nobilis Lour) ×Poncirus trifoliata ((L.) Raf.) hybrids as salt stress-tolerant citrus rootstocks

Mary-Rus Martínez-Cuenca,Maria Angeles Forner-Giner,Amparo Primo-Capella 한국원예학회 2021 Horticulture, Environment, and Biotechnology Vol.62 No.3

This work evaluates new citrus hybrid tolerance to salt stress compared to Carrizo citrange. Growth parameters, ion concentration,photosynthetic parameters, leaf water relation, plant damage and proline concentration were assessed in plantsirrigated with 0 (control) or 60 mM of NaCl for 60 days. Some hybrids presented marked salt-stress symptomatology likesharp decreases in plant biomass and RGR parameter, and high leaf burn and abscission percentages. While Cl − accumulationin most salinised genotypes was recorded in all the plant fractions, accumulation occurred in some hybrids only in their aerialorgans. Stomatal conductance also lowered under salt conditions in all the hybrids, whereas the internal CO 2 concentration(Ci) tended to increase. Salt stress lowered the leaf water potentials in all the 0501 hybrids. As a response, the salinisedplants induced proline accumulation. The main trait that improved salt tolerance in some genotypes is apparently linked withthe imbalance among Cl − , Na + and K + ions, especially enhanced K + uptake and transport rates which delay plant damage.

Experimental modal analysis of transverse-cracked rails- influence of the cracks on the real track behavior

Laura Montalbán Domingo,Beatriz Baydal Giner,Clara Zamorano Martín,Julia I. Real Herráiz 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.5

Rails are key elements in railway superstructure since these elements receive directly the train load transmitted by the wheels. Simultaneously, rails must provide effective stress transference to the rest of the track elements. This track element often deteriorates as a consequence of the vehicle passing or manufacturing imperfections that cause in rail several defects. Among these rail defects, transverse cracks highlights and are considered a severe pathology because they can suddenly trigger the rail failure. This study is focused on UIC-60 rails with transverse cracks. A 3-D FEM model is developed in ANSYS for the flawless rail in which conditions simulating the crack presence are implemented. To account for the inertialoss of the rail as a consequence of the cracking, a reduction of the bending stiffness of the rail is considered. The numerical models have been calibrated using the first four bending vibration modes in terms of frequencies. These vibration frequencies have been obtained using the Experimental Modal Analysis technique, studying the changes in the modal parameters of the rails induced by the crack and comparing the results obtained by the model with experimental results. Finally, the calibrated and validated models for the single rail have been implemented in a complete railway ballasted track FEM model in order to study thestatic influence of the cracks on the rail deflection caused by a load passing.

Key role of boron compartmentalisation-related genes as the initial cell response to low B in citrus genotypes cultured in vitro

Mary-Rus Martínez-Cuenca,Amparo Primo-Capella,Maria Angeles Forner-Giner 한국원예학회 2019 Horticulture, Environment, and Biotechnology Vol.60 No.4

This work compared the expression of the main B transport-related genes (some members of the aquaporin family - NIP5 , TIP5 and PIP1 - and some effl ux-B transporters - BOR1 and BOR4 -), and the response of some physiological parameters in two citrus species [ Citrus macrophylla W. (CM) and Citrus aurantium L. (CA)] under moderate and low boron (B) conditions. Seedlings were cultured “in vitro” in media supplemented with 50 or 0 μM H 3 BO 3 . NIP5 , BOR1 and PIP1 expressions were enhanced by low B levels in both genotypes. TIP5 was down-regulated in the roots and leaves of the CA0 seedlings, and in the roots of CM0. BOR4 also lowered in the roots of both species at 0 μM H 3 BO 3 . Consequently, citrus species showed a common tolerance mechanism to low B conditions based on the synergism among transport channel NIP5, non-selective aquaporin PIP1 and transporter BOR1, and the impairment of genes TIP5 and BOR4 related with tolerance responses to B-toxic conditions. However, the CA genotype displayed low B symptoms earlier than CM (reduced plant biomass, length, relative growth rate and chlorophyll content). Proline concentration was higher in CM0 than in CA0 leaves, while the latter also enhanced malonaldehyde content. Although both plants had similar B concentrations, they diff ered in B content and B partitioning fractions. Whereas the CA genotype was more aff ected by lack of B treatment as more B was needed inside the cell, the more minimal need of cell B in CM favoured its allocation in the insoluble fraction and allowed growth in this genotype. In conclusion, B compartmentalisation seems critical in tolerance to low B level in citrus.

Electrically Enhanced Readout System for a High-Frequency CMOS-MEMS Resonator

Arantxa Uranga,Joan Lluis Lopez,Jordi Teva,Francesc Torres,Joan Josep Giner,Gonzalo Murillo,Gabriel Abadal,Nuria Barniol,Jaume Verd 한국전자통신연구원 2009 ETRI Journal Vol.31 No.4

The design of a CMOS clamped-clamped beam resonator along with a full custom integrated differential amplifier, monolithically fabricated with a commercial 0.35 m CMOS technology, is presented. The implemented amplifier, which minimizes the negative effect of the parasitic capacitance, enhances the electrical MEMS characterization, obtaining a 48×108 resonant frequency-quality factor product (Q×fres) in air conditions, which is quite competitive in comparison with existing CMOS-MEMS resonators.

Value Extrapolation Technique to Solve Retrial Queues: A Comparative Perspective

Jose Manuel Gimenez-Guzman,Ma Jose Domenech-Benlloch,Vicent Pla,Vicente Casares-Giner,Jorge Martinez-Bauset 한국전자통신연구원 2008 ETRI Journal Vol.30 No.3

While the retrial phenomenon plays an important role in communication networks and should not be ignored, retrial systems do not present an exact analytic solution, so approximate techniques are required. To the best of our knowledge, all the existing techniques are based on computing the steady states probabilities. We propose another approach based on the relative state values which appear in the Howard equations. The results of the numerical evaluation carried out show that this solution outperforms previous approaches in terms of both accuracy and computation time.

Development of Compatibilized Polyamide 1010/Coconut Fibers Composites by Reactive Extrusion with Modified Linseed Oil and Multi-functional Petroleum Derived Compatibilizers

L. Quiles-Carrillo,R. Balart,T. Boronat,S. Torres-Giner,D. Puglia,F. Dominici,L. Torre 한국섬유공학회 2021 Fibers and polymers Vol.22 No.3

This work reports the preparation and characterization of fully bio-based polymer composites with coconut fibers(CFs) as an alternative to wood-plastic composites (WPCs), typically based on petroleum derived materials. Polyamide 1010(PA1010) was melt-extruded with 20 wt% of CFs and, after that, shaped into pieces by injection molding. Four differentmulti-functionalized compatibilizers were tested to increase the polymer-fiber interactions with the subsequent improvementon toughness. These consisted of two chemically modified vegetable oils, namely maleinized and epoxidized linseed oil (MLOand ELO) respectively, and two commercial additives derived from petroleum and based on glycidyl functionality, that is,low-functionality epoxy-based styrene-acrylic oligomer (ESAO) and polystyrene-glycidyl methacrylate random copolymer(PS-GMA). The addition of all four compatibilizers improved both the mechanical and thermomechanical properties of thecomposites, thus resulting in high-performance composite materials with relatively low water uptake. Furthermore, themorphology of the obtained composites revealed an extraordinary embedment of the fibers into the biopolymer matrix, whichplays a crucial role in improving toughness. Among all the tested compatibilizers, those derived from vegetable oils can beconsidered the most interesting ones due to they offer a more sustainable solution.