Vibrations of Short Span Railway Bridges for High Speed Lines

The physical model based on moving constant loads is widely used for the analysis of railway bridges. Nevertheless, this model is not well-suited for the study of short span bridges (L<=15-20 m), and the results it produces (displacements and accelerations) are much greater than those obtained experimentally. In this paper two factors are analysed which are believed to have an influence in the dynamic behaviour of short bridges. These two factors are not accounted for by the moving loads model and are the following: the distribution of the loads due to the presence of the sleepers and ballast layer, and the train-bridge interaction. Several numerical simulations have been performed in order to decide on their influence, and the results are presented and discussed herein

Evaluation of optical techniques for characterising soil organic matter quality in agricultural soils

Soil organic matter (SOM) is one of the main global carbon pools. It is a measure of soil quality as its presence increases carbon sequestration and improves physical and chemical soil properties. The determination and characterisation of humic substances gives essential information of the maturity and stresses of soils as well as of their health. However, the determination of the exact nature and molecular structure of these substances has been proven difficult. Several complex techniques exist to characterise SOM and mineralisation and humification processes. One of the more widely accepted for its accuracy is nuclear magnetic resonance (NMR) spectroscopy. Despite its efficacy, NMR needs significant economic resources, equipment, material and time. Proxy measures like the fluorescence index (FI), cold and hot-water extractable carbon (CWC and HWC) and SUVA-254 have the potential to characterise SOM and, in combination, provide qualitative and quantitative data of SOM and its processes. Spanish and British agricultural cambisols were used to measure SOM quality and determine whether similarities were found between optical techniques and 1H NMR results in these two regions with contrasting climatic conditions. High correlations (p < 0.001) were found between the specific aromatic fraction measured with 1H NMR and SUVA-254 (Rs = 0.95) and HWC (Rs = 0.90), which could be described using a linear model. A high correlation between FI and the aromatics fraction measured with 1H NMR (Rs = −0.976) was also observed. In view of our results, optical measures have a potential, in combination, to predict the aromatic fraction of SOM without the need of expensive and time consuming techniques

Behaviour during Malolactic Fermentation of Three Strains of Oenococcus oeni Used as Direct Inoculation and Acclimatisation Cultures

The behaviour in malolactic fermentation (MLF) of an autochthonous strain of Oenococcus oeni, C22L9,isolated from a winery in Castilla-La Mancha (Spain), and of two other commercial strains of O. oeni, PN4and Alpha (Lallemand Inc.), inoculated by direct inoculation (MBR®) and after a short acclimatisationphase (1-STEP®), was studied. Strain C22L9 carried out MLF slightly faster than the two other commercialstrains, leading to a lower increase in volatile acidity and in 2,3-butanedione and 3-hydroxy-2-butanoneconcentrations, a higher lactic acid content, lower degradation of citric acid and increased degradation ofethanol. No great differences were observed in the duration of MLF, although the acclimatisation cultureswere slightly faster, or in the composition of the wines when using the O. oeni strains in the form of MBR®or 1-STEP® cultures. The tasters did not detect significant differences in the wines obtained from the samestrain of O. oeni in the two inoculation formats

Problemas de salud y factores determinantes del número de visitas a demanda en pacientes hiperutilizadores de un centro de salud

ObjetivosDescribir las características sociodemográficas y problemas de salud que presentan los pacientes hiperconsultadores de un centro de salud y determinar los factores que explican el número de visitas solicitadas en consulta demanda del médico de familia.DiseñoDescriptivo, retrospectivo. Análisis multivariante: regresión lineal múltiple.EmplazamientoCentro de salud urbano.PacientesPacientes que han solicitado cita para consulta demanda en el centro de salud en al menos nueve ocasiones durante 1999 (n = 7.852). Muestra aleatoria de 386 pacientes (alfa, 0,05; precisión, 95%).Mediciones y resultados principalesVariable dependiente: número de consultas demanda solicitadas en 1999. Variables independientes: edad, tamaño familiar, zona residencia, activo o pensionista, inclusión en programas, problemas de salud (CIAP-2), número de fármacos en prescripción repetida (clasificación anatómica), incapacidad laboral temporal (IT). Los hiperconsultadores son un 57,8% (IC, 52,9-62,7%) mujeres; edad media, 55 años (DE, 18,5); tamaño familiar, 2,7 miembros (DE, 1,457); 58,8% pensionistas; número medio de citas, 15 (DE, 6,7); consumo medio, 1,58 (DE, 2,46) fármacos de forma habitual; inclusión en programas: 37,7%, hipertensión; 16%, diabetes; 17%, dislipemia; 16%, consulta de enfermería. Patologías más prevalentes: cardiocirculatorias (43,8%), endocrinometabólicas (32%), traumatológicas (26,7%) y salud mental (21%). El modelo de regresión incluye las variables edad, número de fármacos y haber estado en IT.ConclusionesLos hiperconsultadores de nuestro centro de salud son mujeres de edad media con problemas de salud física de evolución crónica y problemas de salud mental. El número de visitas está relacionado con la edad y las necesidades administrativas: medicación y bajas.ObjectivesTo describe the social and demographic characteristics and health problems of over-users of a health centre and to determine the number of attendances requested on demand at the general medical clinic.DesignRetrospective and descriptive. Multivariate analysis: multiple linear regression.SettingUrban health centre.PatientsPatients who requested a consultation at the health centre on at least nine occasions in 1999 (N = 7852). Random sample of 386 patients (alpha 0.05, 95% accuracy).Measurements and main resultsDependent variable: number of on-demand consultations requested in 1999. Independent variables: age, family size, area of residence, active or pensioner, inclusion in programmes, health problems (CIAP-2), number of drugs on repeat prescription (Anatomical Classification), short-term time off work. 57% of over-users were women (CI, 52.9-62.7%); mean age 55 (SD 18.5); family size 2.7 members (SD 1.457); 58.8% pensioners. Mean number of appointments 15 (SD 6.7). Mean habitual consumption of 1.58 medicines (SD 2.46). Inclusion in programmes: 37.7% hypertension, 16% diabetes, 17% dyslipaemia, 16% nursing clinic. Most prevalent pathologies: cardiocirculatory (43.8%), endocrino-metabolic (32%), traumatology (26.7%) and mental health (21%). The regression model included the variables of age, number of medicines and having had short-term time off.ConclusionsOver-users of our health centre are middle-aged women with chronic physical health problems and with mental health problems. The number of attendances is related to age and administrative requirements: medication and sick notes

Aplicación de quitosano modificado en el tratamiento de aguas residuales de tenerías

In this study, the adsorption capacity of chromium VI in copper-modified chitosan (Chitosan-Cu) and in zinc-modified chitosan (Chitosan-Zn), and its application in tannery wastewater were compared. This work included the study of the pH of maximum adsorption capacity in a range of 3 to 6 and the adsorption equilibrium of Cr (VI) at different concentrations (from 1.0 to 750.0 mg / l) and different masses of modified bio-adsorbents (5 and 2 g). The results showed that the adsorption of chromium VI in the two modified bioadsorbents depends strongly on the pH of the solution, where the highest percentage of chromium VI removal was reached at pH 3. The evaluation of the data Experiments of the adsorption equilibrium of Cr (VI) applying the Langmuir and Freundlich models shows that in all cases there was a better fit of the data to the Freundlich model and that the maximum adsorption capacity was reached in the Chitosan-Cu adsorbent. Also, the results indicated that the Chitosan-Cu adsorbent was more effective in the removal of Cr VI from tannery wastewater with 98%.En este estudio se comparó la capacidad de adsorción de cromo VI en quitosano modificado con cobre (Quitosano–Cu) y en quitosano modificado con cinc (Quitosano–Zn), y su aplicación en aguas residuales de tenería. Este trabajo incluyó el estudio del pH de máxima capacidad de adsorción en un rango de 3 a 6 y el equilibrio de adsorción de Cr (VI) a diferentes concentraciones (de 1.0 a 750.0 mg/l) y diferentes masas de bio-adsorbentes modificados (5 y 2 g). Los resultados muestran que la adsorción del ion metálico en los dos bio-adsorbentes modificados depende fuertemente del pH de la solución, donde el mayor porcentaje de remoción de cromo VI se alcanzó a pH 3. Por su parte, la evaluación de los datos experimentales del equilibrio de adsorción de Cr (VI), aplicando los modelos de Langmuir y Freundlich, mostró que en todos los casos hubo un mejor ajuste de los datos al modelo de Freundlich y que la capacidad máxima de adsorción fue alcanzada en el adsorbente Quitosano–Cu. Así también, los resultados indicaron que el adsorbente Quitosano–Cu fue más efectivo en la remoción de Cr VI de las aguas residuales de tenería con un 98%

Fiber beam model for fire response simulation of axially loaded concrete filled tubular columns

This paper presents a fiber beam model for the fire response simulation of concrete filled tubular columns of circular section under concentric axial load. The model consists of two parallel components, one with a circular tubular steel section, and the other with a solid circular concrete section. The components interact with nonlinear longitudinal and transverse links at the end nodes. The element is formulated on a system without rigid body modes and accounts for large displacement geometry through the co-rotational formulation connected both longitudinally and transversely at their nodes by link elements. The model is capable of representing different types of concrete infill of the steel tubes: plain, reinforced and steel fiber reinforced concrete of normal or high strength. It is validated against experimental data from column specimens under fire. The results are also compared against a three-dimensional finite element model characterized by its accuracy of fire response simulation.The authors express their sincere gratitude to Prof. Filip C. Filippou for his comments to the paper. Also to the Spanish "Ministerio de Ciencia e Innovacion" for the help provided through the Project BIA2009-9411; to the Valencian autonomous community institution "Generalitat Valenciana" for the support given by means of the ACIF/2010/219 Program; and to the European Union for its collaboration through the FEDER funds.Ibáñez Usach, C.; Romero, ML.; Hospitaler Pérez, A. (2013). Fiber beam model for fire response simulation of axially loaded concrete filled tubular columns. Engineering Structures. 56:182-193. https://doi.org/10.1016/j.engstruct.2013.05.004S1821935

State transfer in dissipative and dephasing environments

By diagonalization of a generalized superoperator for solving the master equation, we investigated effects of dissipative and dephasing environments on quantum state transfer, as well as entanglement distribution and creation in spin networks. Our results revealed that under the condition of the same decoherence rate $\gamma$, the detrimental effects of the dissipative environment are more severe than that of the dephasing environment. Beside this, the critical time $t_c$ at which the transfer fidelity and the concurrence attain their maxima arrives at the asymptotic value $t_0=\pi/2\lambda$ quickly as the spin chain length $N$ increases. The transfer fidelity of an excitation at time $t_0$ is independent of $N$ when the system subjects to dissipative environment, while it decreases as $N$ increases when the system subjects to dephasing environment. The average fidelity displays three different patterns corresponding to $N=4r+1$, $N=4r-1$ and $N=2r$. For each pattern, the average fidelity at time $t_0$ is independent of $r$ when the system subjects to dissipative environment, and decreases as $r$ increases when the system subjects to dephasing environment. The maximum concurrence also decreases as $N$ increases, and when $N\rightarrow\infty$, it arrives at an asymptotic value determined by the decoherence rate $\gamma$ and the structure of the spin network.Comment: 12 pages, 6 figure

Advances in the analysis of short span railway bridges for high-speed lines

The physical model based on moving constant loads is widely used for the analysis of railway bridges. Nevertheless, the moving loads model is not well suited for the study of short bridges (L⩽20–25 m) since the results it produces (displacements and accelerations) are much greater than those obtained from more sophisticated ones. In this paper two factors are analysed which are believed to have an influence in the dynamic behaviour of short bridges. These two factors are not accounted for by the moving loads model and are the following: the distribution of the loads due to the presence of the sleepers and ballast layer, and the train–bridge interaction. In order to decide on their influence several numerical simulations have been performed. The results are presented and discussed herein