Influence of Embankments with Parapets on the Cross-Wind Turbulence Intensity at the Contact Wire of Railway Overheads

Winds as an environmental factor can cause significant difficulties for the railway system operation. The railway overhead has been particularly vulnerable to cross-winds related problems, such as development of undamped oscillations due to galloping phenomenon. The installation of windbreaks to decrease the aerodynamic loads on the train can affect the loads on railway overheads triggering cable galloping. One essential parameter to indicate the influence of the parapet wake on the catenary contact wire is the turbulence intensity. In this paper the results of an experimental analysis of the turbulence intensity due to the presence of parapets carried out in a wind tunnel are reported. Embankments equipped with different parapets have been tested and turbulence intensity has been measured at both contact wire locations, windward and leeward. The relative influence of the parapets is measured through a reduced turbulence intensity, defined as the ratio between the turbulence intensity measured with parapet and the turbulence intensity in the case without any parapet on the embankment. In general the reduced turbulence intensity increases as the height of the parapet increases

Consumer Response to the Disposal of Potentially Harmful Products: The Product Life-Cycle, Consumer Activism, and Subjective Well-Being across Borders

This research attempts to uncover the factors that influence protest behaviors, specifically, consumer activism intention and how the factors are different between industrialized and developing countries. This research draws from the Values-Norms, Beliefs (VBN) Theory and the Not-In-My-Backyard (NIMBY) framework to test protest intention between the United States and Mexico regarding the improper disposal of potentially harmful products across borders. Further, this research attempts to extend the VBN-Theory to include trust-in-government, attitude towards the firm, and subjective well-being. The findings of this research indicate that the VBN Theory is confirmed not only in the United States, but also in Mexico and that the VBN Theory is a superior explanation of protest intention rather than the NIMBY framework. This research contributes to theory by providing evidence that trust-in-government leads to consumer activism intention in Mexico, but not in the United States. Additionally, Mexican respondents are more likely to experience subjective well-being when engaging in consumer activism behavior while US respondents do not

Invariant Smooth Quartic Surfaces by all Finite Primitive Groups of PGL⁡4(C)\operatorname{PGL}_4(\mathbb{C})

For each finite primitive subgroup $G$ of $\operatorname{PGL}_4(\mathbb{C})$, we find all the smooth $G$-invariant quartic surfaces. We also find all the faithful representations in $\operatorname{PGL}_4(\mathbb{C})$ of the smooth quartic $G$-invariant surfaces by the groups: $\mathfrak{A}_5,\mathfrak{S}_5, \operatorname{PSL_2(\mathbb{F}_7)},\mathfrak{A}_6,\mathbb{Z}_2^4\rtimes\mathbb{Z}_5$ and $\mathbb{Z}_2^4\rtimes D_{10}$. The primitive representation of these groups are precisely the subgroups of $\operatorname{PGL}_4(\mathbb{C})$ for which $\mathbb{P}^3$ is not $G$-super rigid. As a byproduct, we show that the smooth quartic surface with the biggest group of projective automorphism is given by $\{ x_0^4 + x_1^4 + x_2^4 + x_3^4 + 12 x_0 x_1 x_2 x_3= 0\}$ (unique up to projective equivalence).Comment: 22 pages, comments are welcom

Consumer Propensity to Adopt Illicit Goods: Theory, Methods, and Results

The purpose of this study is to examine consumer propensity to adopt illicit goods. The adoption of illicit goods is a worldwide problem that undermines legitimate markets, funds criminal organizations, and harms the most vulnerable in society. International organizations, such as World Economic Forum, have called for the study of the demand of illicit products. Research is crucial to understanding the demand for these products and can contribute to public policy addressing this issue. This research uses two theoretical frameworks: The Theory of Planned Behavior and the Theory of Marketing Ethics. Using the Theory of Planned Behavior, research results suggest that subjective norms influence consumers’ propensity to adopt illicit goods. Using the Theory of Marketing Ethics, research on consumers’ ethical orientation found that both teleological and deontological orientations influence consumers’ ethical judgement and intention. Theoretical and methodological conclusions are derived, and managerial and policy implications are offered

A simplified approach to determine aerodynamic damping of railway overheads

The railway overhead (or catenary) is the system of cables responsible for providing electric current to the train. This system has been reported as wind-sensitive (Scanlon et al., 2000), and particularly to the occurrence of galloping phenomena. Galloping phenomena of the railway overhead consists of undamped cable oscillations triggered by aerodynamic forces acting on the contact wire. As is well known, aerodynamic loads on the contact wire depends on the incident flow mean velocity and the angle of attack. The presence of embankments or hills modifies both vertical velocities profiles and angles of attack of the flow (Paiva et al., 2009). The presence of these cross-wind related oscillations can interfere with the safe operation of the railway service (Johnson, 1996). Therefore a correct modelling of the phenomena is required to avoid these unwanted oscillations

Extracting energy from Vortex-Induced Vibrations: A parametric study

Here, Vortex-Induced Vibrations (VIVs) of a circular cylinder are analyzed as a potential source for energy harvesting. To this end, VIV is described by a one-degree-of-freedom model where fluid forces are introduced from experimental data from forced vibration tests. The influence of some influencing parameters, like the mass ratio m∗ or the mechanical damping ζ in the energy conversion factor is investigated. The analysis reveals that: (i) the maximum efficiency ηM is principally influenced by the mass-damping parameter m∗ζ and there is an optimum value of m∗ζ where ηM presents a maximum; (ii) the range of reduced velocities with significant efficiency is mainly governed by m∗, and (iii) it seems that encouraging high efficiency values can be achieved for high Reynolds numbers

The Yamabe invariant for axially symmetric two Kerr black holes initial data

An explicit 3-dimensional Riemannian metric is constructed which can be interpreted as the (conformal) sum of two Kerr black holes with aligned angular momentum. When the separation distance between them is large we prove that this metric has positive Ricci scalar and hence positive Yamabe invariant. This metric can be used to construct axially symmetric initial data for two Kerr black holes with large angular momentum.Comment: 14 pages, 2 figure

Revisión taxonómica del género Hypseocharis en Perú y Bolivia

In the present study we revised the genus Hypseocharis in Bolivia and Peru. A total number of 105 herbarium specimens were revised to evaluate the morphological diversity across the range of the genus. In a subset of 24 complete individuals a multivariate morphometric analysis was performed to evaluate the morphological characters historically used to differentiate the “species” of the genus Hypseocharis. A revision of the herbarium material indicated that there are no sharp lines dividing the different “species” with the only exception of H. tridentata. The multivariate analysis indicated that H. bilobata, H. malpasensis and H. pedicularifolia all occupy the same morphospace as H. pimpinellifolia and there are no individual morphological characters or suites of characters permitting the differentiation of distinct taxa. This confirms earlier findings from Argentina: There are only two species in the genus, widespread Hypseocharis pimpinellifolia and H. tridentata. Hypseocharis pilgeri, originally described from Peru, can also not be differentiated from H. pimpinellifolia. We propose the recognition of only two species: H. pimpinellifolia with variously pinnate to bipinnate leaves with a terminal leaflet at most marginally larger than the lateral ones, flowers with 15 anthers and capsular fruits as differing from H. tridentata with pinnate leaves with the terminal leaflet much larger than the lateral ones, flowers with 5 anthers and schizocarpic fruits. Hypseocharis pimpinellifolia is a widespread and polymorphic species, ranging from Ancash (Peru) to La Rioja (Argentina) and comprises forms with white, yellow, orange, and red corollas and with simply pinnate to very finely bipinnate leaves.En el presente estudio se realizó una revisión taxonómica del género Hypseocharis en Bolivia y Perú. Se analizó la diversidad morfológica abarcando toda la distribución geográfica del género Hypseocharis utilizando 105 especímenes de herbario. Un análisis multivariado morfométrico fue aplicado a 24 individuos completos para evaluar los caracteres históricos utilizados para diferenciar las especies dentro del género. La revisión del material de herbario mostró una distinción de la especie H. tridentata, pero no se confirmó una clara separación entre las “especies” H. bilobata, H. malpasensis, H. pedicularifolia y H. pimpinellifolia. Todas ocupan el mismo morfo espacio con similares caracteres morfológicos, apoyando previos estudios en Argentina, donde solamente se describieron dos especies: H. pimpinellifolia y H. tridentata, esta última proveniente de Argentina y con solo un espécimen de Bolivia. Nuestros resultados también mostraron que H. pilgeri, originalmente descrita en Perú, tampoco se diferencia de H. pimpinellifolia. Por lo tanto, proponemos la distinción de solamente dos especies en el género: H. pimipinellifolia con hojas variables pinnadas o bipinnadas, con foliolos terminales un poco más grandes que los foliolos laterales; flores con 15 anteras y tipo de fruto capsular. Mientras que H. tridentata posee hojas pinnadas con foliolos terminales mucho más grandes que los laterales; flores con 5 anteras y tipo de fruto esquizocarpo. Hypseocharis pimpinellifolia es una especie ampliamente distribuida desde Ancash (Perú) hasta La Rioja (Argentina) morfológicamente variable incluyendo varios tipos de hojas, desde simples pinnadas hasta bipinnadas y flores blancas, amarillas, naranjas o rojas