The effect of Windbreaks on Railway Overheads subject to Cross-Winds at O Eixo Viaduct

A measurement investigation, at ADIF's test site at the O Eixo viaduct which is on the Spanish Santiago-Ourense high speed railway line, has been carried out during the last year. The main goal of the investigation is to study the effect of the cross-wind on railway overheads (catenaries) and the influence of the presence of windbreaks on the wind-induced motion of the railway overhead. A description of the O Eixo viaduct test site is presented in this paper, including the installed windbreaks, the sensor and power supply systems. Three catenary spans has been instrumented at the center point of the catenary span contact wire with one ultrasonic anemometer and two unidirectional accelerometers. Additionally, another ultrasonic anemometer placed in the central catenary span has been installed to provide reference wind data. Wind roses of wind speed and standard deviation of the accelerometers are presented. As expected, the four wind roses look very similar and the two dominant directions close to the perpendicular to the bridge longitudinal axes, north and south have been identified. The wind roses of the standard deviation of the acceleration shows that the acceleration of the catenary contact wire is related to the directions of the two dominant winds. The vertical standard deviation of the acceleration is higher than the horizontal one for the spans with windbreaks. It has also been observed that the presence of the windbreaks modifies the wind flow leading to a wind-induced motion of the catenary contact wire which shows a higher variability than the corresponding unprotected case. On the one hand, the baseline southerly wind configuration (south wind, windbreaks in the windward side and catenary in the leeward side) influence both the mean speed at the catenary and the turbulence intensity. On the other hand, the northerly wind configuration, windbreaks in the leeward side and catenary in the windward side, provide a reference to the response of the catenary for an unprotected railway overhead, and, as it is expected, the windbreak influence is much more reduced compared to the southerly wind configuration. Both the height of the windbreak and the eaves contribute to the increase in the turbulence intensity at the catenary contact wire height. It can be seen that the height of the windbreak plays a crucial role in the increase of turbulence intensity, much more intense than the presence of the windbreak eave.

A 2D computational parametric analysis of the sheltering effect of fences on a railway vehicle standing on a bridge and experiencing crosswinds

In a crosswind scenario, the risk of high-speed trains overturning increases when they run on viaducts since the aerodynamic loads are higher than on the ground. In order to increase safety, vehicles are sheltered by fences that are installed on the viaduct to reduce the loads experienced by the train. Windbreaks can be designed to have different heights, and with or without eaves on the top. In this paper, a parametric study with a total of 12 fence designs was carried out using a two-dimensional model of a train standing on a viaduct. To asses the relative effectiveness of sheltering devices, tests were done in a wind tunnel with a scaled model at a Reynolds number of 1 × 105, and the train’s aerodynamic coefficients were measured. Experimental results were compared with those predicted by Unsteady Reynolds-averaged Navier-Stokes (URANS) simulations of flow, showing that a computational model is able to satisfactorily predict the trend of the aerodynamic coefficients. In a second set of tests, the Reynolds number was increased to 12 × 106 (at a free flow air velocity of 30 m/s) in order to simulate strong wind conditions. The aerodynamic coefficients showed a similar trend for both Reynolds numbers; however, their numerical value changed enough to indicate that simulations at the lower Reynolds number do not provide all required information. Furthermore, the variation of coefficients in the simulations allowed an explanation of how fences modified the flow around the vehicle to be proposed. This made it clear why increasing fence height reduced all the coefficients but adding an eave had an effect mainly on the lift force coefficient. Finally, by analysing the time signals it was possible to clarify the influence of the Reynolds number on the peak-to-peak amplitude, the time period and the Strouhal number.

Analysis of a rate-adaptive reconciliation protocol and the effect of leakage on the secret key rate

Quantum key distribution performs the trick of growing a secret key in two distant places connected by a quantum channel. The main reason is so that the legitimate users can bound the information gathered by the eavesdropper. In practical systems, whether because of finite resources or external conditions, the quantum channel is subject to fluctuations. A rate-adaptive information reconciliation protocol, which adapts to the changes in the communication channel, is then required to minimize the leakage of information in the classical postprocessing. We consider here the leakage of a rate-adaptive information reconciliation protocol. The length of the exchanged messages is larger than that of an optimal protocol; however, we prove that the min-entropy reduction is limited. The simulation results, both in the asymptotic and in the finite-length regime, show that this protocol allows to increase the amount of a distillable secret key.

Effect of fire on the microstructure and mechanical response of structural steels for building construction

The research is an exhaustive study of the microstructure and of the stress-strain curves of structural steel S460N at temperatures typical of a fire. It includes a fractographic study of the fracture suifaces of cylindrical specimens, tensile tested at different fire scenarios, explaining the relationship between the failure micromechanisms and temperature. The paper ends with the comparison between the experimentally found strain-stress curves with that one's proposed by the EUROCODE EC3, resulting that in the case of steel S460N these are on the side ofsafety.

Effect of Uncertainty on the Reaction Response in Fencing

Biomecanica del rendimiento en esgrima

Effect of fire on the microstructure and mechanical response of structural steels for building construction

The research is an exhaustive study of the microstructure and of the stress-strain curves of structural steel S460N at temperatures typical of a fire. It includes a fractographic study of the fracture suifaces of cylindrical specimens, tensile tested at different fire scenarios, explaining the relationship between the failure micromechanisms and temperature. The paper ends with the comparison between the experimentally found strain-stress curves with that one's proposed by the EUROCODE EC3, resulting that in the case of steel S460N these are on the side ofsafety.

Effect of Sb on the quantum efficiency of GaInP solar cells

The energy bandgap of GaInP solar cells can be tuned by modifying the degree of order of the alloy. In this study, we employed Sb to increase the energy bandgap of the GaInP and analyzed its impact on the performance of GaInP solar cells. An effective change in the cutoff wavelength of the external quantum efficiency of GaInP solar cells and an effective increase of 50 mV in the open-circuit voltage of GaInP/Ga(In)As/Ge triple junction solar cells were obtained with the use of Sb. Copyright © 2016 John Wiley & Sons, Ltd.

Identification of differentially expressed mRNA in prokaryotic organisms by customized amplification libraries (DECAL): The effect of isoniazid on gene expression in Mycobacterium tuberculosis

Understanding the effects of the external environment on bacterial gene expression can provide valuable insights into an array of cellular mechanisms including pathogenesis, drug resistance, and, in the case of Mycobacterium tuberculosis, latency. Because of the absence of poly(A)+ mRNA in prokaryotic organisms, studies of differential gene expression currently must be performed either with large amounts of total RNA or rely on amplification techniques that can alter the proportional representation of individual mRNA sequences. We have developed an approach to study differences in bacterial mRNA expression that enables amplification by the PCR of a complex mixture of cDNA sequences in a reproducible manner that obviates the confounding effects of selected highly expressed sequences, e.g., ribosomal RNA. Differential expression using customized amplification libraries (DECAL) uses a library of amplifiable genomic sequences to convert total cellular RNA into an amplified probe for gene expression screens. DECAL can detect 4-fold differences in the mRNA levels of rare sequences and can be performed on as little as 10 ng of total RNA. DECAL was used to investigate the in vitro effect of the antibiotic isoniazid on M. tuberculosis, and three previously uncharacterized isoniazid-induced genes, iniA, iniB, and iniC, were identified. The iniB gene has homology to cell wall proteins, and iniA contains a phosphopantetheine attachment site motif suggestive of an acyl carrier protein. The iniA gene is also induced by the antibiotic ethambutol, an agent that inhibits cell wall biosynthesis by a mechanism that is distinct from isoniazid. The DECAL method offers a powerful new tool for the study of differential gene expression.

Conformational influences of glycosylation of a peptide: A possible model for the effect of glycosylation on the rate of protein folding

Improved strategies for synthesis make it possible to expand the range of glycopeptides available for detailed conformational studies. The glycopeptide 1 was synthesized using a new solid phase synthesis of carbohydrates and a convergent coupling to peptide followed by deprotection. Its conformational properties were subjected to NMR analysis and compared with a control peptide 2 prepared by conventional solid phase methods. Whereas peptide 2 fails to manifest any appreciable secondary structure, the glycopeptide 1 does show considerable conformational bias suggestive of an equilibrium between an ordered and a random state. The implications of this ordering effect for the larger issue of protein folding are considered.

DNA immunization: Induction of higher avidity antibody and effect of route on T cell cytotoxicity

Immunizations of mice with plasmid DNAs encoding ovalbumin (OVA), human Ig, and hen egg lysozyme were compared with doses of soluble protein (without adjuvant) that induced similar IgG responses. The route of immunization influenced the magnitude of the antibody (Ab) response in that intradermal (i.d.) injection elicited higher IgG Ab levels than i.m. injection in both DNA- and protein-immunized mice. Although total IgG levels were similar to soluble protein controls, the avidity of the anti-OVA Abs generated by DNA immunization were 100- and 1,000-fold higher via the i.m. or i.d. route, respectively. However, despite the generation of high-avidity Ab in DNA-immunized mice, germinal centers could not be detected in either DNA- or protein-immunized mice. Examination of the IgG subclass response showed that IgG2a was induced by i.m. DNA immunization, coinciding with elevated interferon γ production, whereas a dominant and elevated IgG1 response, coinciding with detectable interleukin 4 production, was generated after i.d. immunization with DNA or soluble OVA and hen egg lysozyme but not human Ig protein. As expected, cytotoxic T cell (CTL) responses could be detected only after DNA immunization. I.d. immunization produced the strongest CTL responses early (2 weeks) but was similar to i.m. later. Therefore, DNA immunization can differ from protein immunization by its ability to induce rapid CTL responses and higher avidity Ab, both of which are advantageous for vaccination.

Effect of age on in vivo rates of mitochondrial protein synthesis in human skeletal muscle

A progressive decline in muscle performance in the rapidly expanding aging population is causing a dramatic increase in disability and health care costs. A decrease in muscle endurance capacity due to mitochondrial decay likely contributes to this decline in muscle performance. We developed a novel stable isotope technique to measure in vivo rates of mitochondrial protein synthesis in human skeletal muscle using needle biopsy samples and applied this technique to elucidate a potential mechanism for the age-related decline in the mitochondrial content and function of skeletal muscle. The fractional rate of muscle mitochondrial protein synthesis in young humans (24 ± 1 year) was 0.081 ± 0.004%·h−1, and this rate declined to 0.047 ± 0.005%·h−1 by middle age (54 ± 1 year; P < 0.01). No further decline in the rate of mitochondrial protein synthesis (0.051 ± 0.004%·h−1) occurred with advancing age (73 ± 2 years). The mitochondrial synthesis rate was about 95% higher than that of mixed protein in the young, whereas it was approximately 35% higher in the middle-aged and elderly subjects. In addition, decreasing activities of mitochondrial enzymes were observed in muscle homogenates (cytochrome c oxidase and citrate synthase) and in isolated mitochondria (citrate synthase) with increasing age, indicating declines in muscle oxidative capacity and mitochondrial function, respectively. The decrease in the rates of mitochondrial protein synthesis is likely to be responsible for this decline in muscle oxidative capacity and mitochondrial function. These changes in muscle mitochondrial protein metabolism may contribute to the age-related decline in aerobic capacity and muscle performance.