Occurrence Of Various Phenomena Research Articles

Vibrations of laminated deep curved beams under moving loads

In this study, the forced and free vibrations of a laminated curved beam under moving loads are analyzed. Also, a detailed parametric analysis is performed to clarify the influence of various parameters such as stacking sequence and load speed on the vibrational behavior of the system. Mathematical closed-form expressions for the occurrence of various phenomena such as resonance, maximum resonance, resonance disappearance and two types of cancellation are presented. The fundamental frequency of the system is extracted and compared with the available results in the literature. The accuracy of results which are obtained from the analytical approach is validated with that of the numerical solution. Furthermore, for the first time in this paper, it is shown that the laminated curved beams under moving loads are prone to experience cancellation disappearance phenomenon. It is concluded that the necessary conditions for the occurrence of various phenomena can be provided by fine-tuning of layup configuration. Moreover, the results revealed that resonance speeds are equal in both symmetric and non-symmetric cross-ply layups, and are higher than those of other layup types. The modeling and results presented in this study could be beneficial for engineers designing and optimizing high-speed transportation systems.

Area-Based Topic Modeling and Visualization of Social Media for Qualitative GIS

Qualitative geographic information systems (GIS) has progressed in meaningful ways since early calls for a qualitative GIS in the 1990s. From participatory methods to the invention of the participatory geoweb and finally to geospatial social media sources, the amount of information available to nonquantitative GIScientists has grown tremendously. Recently, researchers have advanced qualitative GIS by taking advantage of new data sources, like Twitter, to illustrate the occurrence of various phenomena in the data set geospatially. At the same time, computer scientists in the field of natural language processing have built increasingly sophisticated methods for digesting and analyzing large text-based data sources. In this article, the authors implement one of these methods, topic modeling, and create a visualization method to illustrate the results in a visually comparative way, directly onto the map canvas. The method is a step toward making the advances in natural language processing available to all GIScientists. The article discusses the ways in which geography plays an important part in understanding the results presented from the model and visualization, including issues of place and space.

Estuarine margins vulnerability to floods for different sea level rise and human occupation scenarios

Rilo, A., Freire, P., Guerreiro, M., Fortunato, A.B., Taborda, R. 2013. Estuarine margins vulnerability to floods for different sea level rise and human occupation scenarios. In: Conley, D.C., Masselink, G., Russell, P.E. and O’Hare, T.J. (eds.), Proceedings 12 th International Coastal Symposium (Plymouth, England), Journal of Coastal Research, Special Issue No. 65, pp. 820-825, ISSN 0749-0208. Sea level rise (SLR) is increasing the risk of flooding in marginal low-lying estuarine areas. High water levels in estuaries are associated with the simultaneous occurrence of various phenomena ranging from high tidal levels to large fresh-water discharges. The intense and diverse human occupation of some of these marginal areas increases the flood vulnerability, endangering human lives and causing heavy economic and environmental losses. This issue becomes even more relevant since the European Floods Directive establishes mandatory guidelines to all member states regarding flood risk assessment, integrating flood maps with territorial characteristics. The present study aims to assess the vulnerability to floods of a specific area in Tagus estuary, by integrating hydrodynamic modelling results with land use cartography. Results suggest that about 16.1% of the estuarine marginal fringe could be flooded for the 2050 scenario, rising up to 23.7% for the 2100 scenario. Moreover, industrial and urban areas will be the most affected sites. Considering future development scenarios planned for that site, the results point to an increasing vulnerability of urban areas and therefore to the relevance of this knowledge in future planning and management guidelines as well as measures to adapt to SLR. The uncertainties and implications of the study are also discussed, and future research topics are indicated.

Experimental Investigation of Air Relative Humidity (RH) Cycling Tests on MEA/Cell Aging in PEMFC Part II: Study of Low RH Cycling Test with Air RH at 62%/0%

AbstractThe effect of low relative humidity (RH) cycling (RHC 62%/0%) on the degradation mechanisms of a single proton exchange membrane fuel cell (5 × 5 cm2) was investigated and compared to a cell operated at constant humidification (RHC = 62%). The overall cell performance loss was near 33 μV h–1, which is greater than the voltage decay under constant RH condition near 3 μV h–1. The electroactive surface was reduced but to an acceptable level. Impedance spectroscopy revealed that the ohmic and charge transfer resistances were reduced by the likely improved hydration of the ionomeric layer at the catalyst due to hydrogen crossover. This was so important that H2 starvation was finally responsible for the collapse of the cell after 650 h. Transmission electron microscopy showed occurrence of various phenomena, e.g., bubbles and pinholes formation in the membrane due to local overheat from hydrogen combustion at the cathode, and thickness reduction of catalytic layers. The water up take obtained by 1H NMR within the membrane electrode assembly (MEA) after low RH cycling reduced by 24% compared to a fresh MEA. Observations are also compared to those obtained at high RH cycling (RHC 62%/100%) presented in Part I of this study [1].

The Role of Political Instability in Stock Market Development and Economic Growth: The Case of Greece

This article examines empirically the relationship between stock market development, political instability and economic growth in Greece. We measure socio‐political instability by constructing an index which captures the occurrence of various phenomena of political violence using time‐series data. The main advantages of analysing political instability in a case study framework using time‐series, in contrast with the widely used cross‐country empirical studies, are: (a) a more careful and in‐depth examination of institutional and historical characteristics of a particular country; (b) the use of a data set comprised of the most appropriate and highest quality measures; and (c) a more detailed exposition of the dynamic evolution of the economy. The empirical results indicate the existence of a strong negative relationship between uncertain socio‐political conditions and the general index of the Athens Stock Exchange (ASE) and support the theoretical hypothesis that uncertain socio‐political conditions affect economic growth negatively, is true for the Greek case.(J.E.L.: G10, G14, O40, C32)

On Human Altruism: The Discrepancy between Normative and Factual Conclusions

Altruism is a successful meme in many human cultures, i.e. self-sacrifice in various forms is held in high regard. In philosophy, being is often seen as equivalent to being altruistic; selfishness is often pitted against altruism, usually without being specified. In spite of the fact that social behaviour can be divided into more categories than these two, the duality between selfishness and is often retained in normative statements also by evolutionary biologists. Many biologists since Darwin (1871) have discussed ethics in an evolutionary framework, and there are several lines of reasoning. First, in some of the literature the main purpose has been to try to explain the occurrence of various phenomena, from actions to sensibilities to rules and systems (e.g. Darwin 1871, Fisher 1958, Trivers 1971, Wilson 1975, Dawkins 1976, Alexander 1987). There are also authors who, like Huxley (1894), regards ethics, the moral process, as separate and antagonistic to evolution, the cosmic process The purpose of the present article is to investigate the evaluation of made by some influential thinkers in evolutionary biology, and to compare this evaluation with their factual conclusions. Our aim is not to criticize these authors, which we admire for their contribution to the understanding of evolutionary processes, but to scrutinize some normative statements in order to shed light on the influence of conventional altruistic ethics. Our main point in the article is that works contrary to reciprocity/cooperation, and that by promoting altruism, the opportunity for reciprocity to work is impaired. This reasoning is based on the following premises: 1) humans have a built-in capacity to act in a manner, but also a built-in capacity to cheat and to manipulate others (e.g. Trivers 1971, 1985), 2) direct and indirect learning will affect the degree to which individuals cooperate or cheat, and normative values and rules for behaviour are part of that learning. If normative values and rules have no effect on behaviour, normative ethics is truly empty: statements without influence. During the last decades theoretical and empirical work in evolutionary biology has produced a coherent explanation of social behaviour (Hamilton 1964, Williams 1966, Trivers 1971, 1985, Wilson 1975), the main conclusion being that the evolution of apparent is due to the effect, on either or potential reciprocators, of selfish genes (Dawkins 1976). Thus, in the following we define as an act that is costly for an actor, that does not benefit kin, and where there is no reasonable expectation of reciprocation. Thus, we exclude reciprocal altruism and kin altruism from Several writers have noted the confusion around the term altruism, caused by a use of the term in both a broad and a specific sense, as well as the need to make a clear distinction. For instance, Ruse (1989) uses with and without quotation marks to denote in a broad and strict sense, respectively. Less confusing is the use of terms like ascetic altruism (Lopreato 1981) and promiscuous altruism (Hardin 1993) suggested for in the specific sense. As mentioned we have preferred to just call it (cf. Bronstein 1994) and let other subgroups like kin altruism and reciprocal altruism do without the term Reciprocal is a self-contradiction. That way we avoid the problem pointed out by Trivers (1971, p. 35): Models that attempt to explain altruistic behavior in terms of natural selection are models designed to take out of altruism. Some workers have questioned the existence of strict Wilson (1979), for instance, questions the of Mother Theresa this because of her belief in salvation through Christianity and good deeds (pp. 172-173). If human behaviour is viewed from the per-

Innovative methods for quantifying poorly known parameters necessary for numerical basin modeling.

Deterministic models, in which mathematical equations are used to predict the occurrence of various phenomena in the subsurface, are widely used today in basin modeling. However, these models suffer from a number of weaknesses, including incorrect or incomplete equations, incorrect constants in the equations, and errors in input variables. Several alternatives to present deterministic basin models are illustrated here by showing their application in describing permeability.Self similarity, the basis of fractal theory, states that many patterns observed on one scale are also present on other scales. Measured permeability data from hand samples of reservoir rocks must be scaled to adequately describe effective formation permeabilities for carrier beds. Self similarity may also be valuable in evaluating the contribution of fracture permeability to fluid flow. A self-similarity approach may be useful even where self similarity is not strictly valid.A new method for predicting the occurrence of overpressuring and the volume of fluid expelled from both normally pressured and overpressured rocks is based on acquisition of empirical data on the maximum sedimentation rates at which normal pressuring can be maintained under well-constrained conditions. The parameters required to use this method (original and present porosity, viscosity of water, compressibility, present thickness, and recent sedimentation rate) can be obtained more accurately from empirical data than the quantities required for calculation of fluid flow from fine-grained rocks using Darcy's law.Tensional fractures can play a dominant role controlling fluid flow in rocks with low matrix permeabilities. The occurrence and intensity of tensile fracturing can be predicted from stress-strain considerations. It may also prove possible to estimate the degree of fracturing by applying self-similarity concepts to fault patterns observed from seismic data, or from empirical data on the occurrence of overpressuring.Great differences exist between human time scales, which govern reservoir engineering, and geologic time scales, which govern fluid movement in basins. Differences that are of acute importance to a reservoir engineer are often of no practical importance for basin modeling. In basin modeling it is most important to specify permeabilities of seals and of fine-grained rocks as they expell water and hydrocarbons. It is also important to determine the minimum permeabilities capable of permitting long-distance lateral fluid flow. Obtaining reliable data for such rocks should be a main objective of research on basin modeling.