A hybrid boundary for the prediction of intake wave dynamics in IC engines

This paper concerns the calculation of wave dynamics in the intake systems of naturally aspirated internal combustion (I.C.) engines. In particular it presents a method for improving the boundary conditions required to solve the one-dimensional Euler equations that are commonly used to describe the wave dynamics in time and space. A number of conclusions are reached in this work. The first relates to the quasi-steady state inflow boundary specified in terms of ingoing and outgoing characteristics that is commonly adopted for engine simulation. This is correctly specified by using the pair of primitive variables pressure (p) and density (ρ) but will be unrealistic at frequencies above a Hemholtz number of 0.1 as only stagnation values po, ρo are used. For the case of I.C. engine intake simulations this sets a maximum frequency of around 300Hz. Above that frequency the results obtained will become increasingly unrealistic. Secondly, a hybrid time and frequency domain boundary has been developed and tested against linear acoustic theory. This agrees well with results obtained using a quasi-steady state boundary at low frequencies (Helmholtz number less than 0.1) and should remain realistic at higher frequencies in the range of Helmholtz number 0.1 - 1.84. Thirdly, the cyclic nature of the operation of the IC engine has been exploited to make use of the inverse Fourier transform to develop an analytical hybrid boundary that functions for non-sinusoidal waves in ducts. The method is self starting, does not rely on iterations over complete cycles and is entirely analytical and therefore is an improvement over earlier hybrid boundaries

Transfinite order dimension

We give two different transfinite extensions of the covering dimension based on the Borst's order of certain families of boundaries of basic open sets. We compare them and we study their main properties

Ediacaran Obduction of a Fore-Arc Ophiolite in SW Iberia: A Turning Point in the Evolving Geodynamic Setting of Peri- Gondwana

The Calzadilla Ophiolite is an ensemble of mafic and ultramafic rocks that represents the transition between lower crust and upper mantle of a Cadomian (peri-Gondwanan) fore arc. Mapping and structural analysis of the ophiolite demonstrates that it was obducted in latest Ediacaran times, because the Ediacaran-Early Cambrian sedimentary series (Malcocinado Formation) discordantly covers it. The ophiolite and emplacement-related structures are affected by Variscan deformation (Devonian-Carboniferous), which includes SW verging overturned folds (D1) and thrusts (D2), upright folds (D3), extensional faults (D4), and later faults (D5). These phases of deformation are explained in the context of Variscan tectonics as the result of the progressive collision between Gondwana and Laurussia. Qualitative unstraining of Variscan deformation reveals the primary geometry of Ediacaran-Cambrian structures and uncovers the generation of east verging thrusts as responsible for the primary obduction of the Calzadilla Ophiolite. Restoration of planar and linear structures associated with this event indicates an Ediacaran, east directed obduction of the ophiolite, that is, emplacement of the Cadomian fore arc onto inner sections of the northern margin of Gondwana. According to regional data, the obduction separates two extension-dominated stages in the tectonic evolution of the African margin of northern Gondwana preserved in southern Europe. Preobduction extension brought about the onset and widening of fore-arc and back-arc basins in the external part of the continent, while postobduction extension facilitated the formation of extensional migmatitic domes, an oceanward migration of back-arc spreading centers across peri-Gondwana, and the eventual opening of a major basin such as the Rheic Ocean

Dimension, inverse limits and GF-spaces

In this paper we characterize (covering) dimension in metrizable spaces in terms of fractal structures. We will also study dimension for compact metric spaces, giving a theorem relating dimension and a certain class of inverse limits, similar to that of Freudenthal

Special Economic Zones, Global Value Chains, and the Degree of Economic Linkages in the Dominican Republic

The Dominican Republic is often considered an example of the successful implementation of Special Economic Zones (henceforth SEZs) in the Western hemisphere. The zones fueled economic growth during the 1980s and 1990s and, while they experienced a sharp decline in employment due in part to the expiry of the end of the Multi-Fiber Agreement and stronger international competition in the textile and apparel industry in 2005, signs of recovery have been observed since 2009. Surgical equipment, chemicals and plastics, and footwear have recently emerged as the new drivers of export dynamism in the zones (World Bank, 2015). The objective of this report is to inform the policy discussion around the developmental impact of SEZs in the Dominican Republic by empirically assessing i) the implications of regulatory reforms aimed at complying with WTO disciplines regarding the elimination of incentives conditioned on export performance for SEZs firms, ii) the extent to which SEZs participate in Global Value Chains, and iii) their linkages with domestic suppliers. The report is organized as follows: The second section presents the historical importance of SEZ as an engine of economic growth in the country. The third section depicts the structural shift in terms of production in SEZs and evaluates the degree of value addition taking place in the Dominican Republic. The fourth section evaluates the degree and evolution of linkages between SEZs and local firms. The fifth section shows the impact of the regulatory changes in the SEZ regimen undertaken to comply with WTO disciplines. Finally, some conclusions and policy recommendations are presented in section six

Light transmitting cement-based material (LTCM) as a green material for building

[EN] In recent years, light-transmitting cement-based materials (LTCM) have become important in the construction of green buildings because these reduce energy consumption for lighting. LTCMs were prepared by adding polymeric optical fibers (POFs) in a high strength self-compacting mortar (SCM). SCM was formulated from Portland cement, fine sand and water reducing admixture following the EFNARC criteria. LTCMs with a constant fiber content (5%) and three fiber diameter (0.75, 1 and 1.5 mm) were prepared by casting fresh SCM into a formwork designed ad hoc to keep the fibers fixed and aligned. Light transmitting performance of LTCM was tested by optical power measures. The effects of fiber diameter and distance between sample and detector on the optical power were evaluated. The compressive strength of hardened SCM reached a value of 69 MPa at an age of 28 days, while the LTCMs maintained sufficient strength for structural purposes. LTCMs are suitable to produce precast blocks and wall panels for application in building facades, signage and decorative art.This work was supported by the Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) under Grant PICT 2016 0445; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Argentina. Special thanks to Ing. Juan Belmonte and Lic Andres Torres for their assistance in mechanical tests.Robles, A.; Arenas, GF.; Stefani, PM. (2020). Light transmitting cement-based material (LTCM) as a green material for building. Journal of Applied Research in Technology & Engineering. 1(1):9-14. https://doi.org/10.4995/jarte.2020.13832OJS9141

Atmospheric Nanoparticles in Photocatalytic and Thermal Production of Atmospheric Pollutants

Atmospheric aerosols which occur above heavily polluted areas such as Mexico City, are characterized and found to be complex materials that have the potential to accelerate important ozone-forming reactions photocatalytically and thermocatalytically. In addition, because the particles are respirable, they may represent a considerable health hazard. The aerosols consist of two intermixed components. The first component consists of amorphous carbonaceous materials of variable composition with fullerene like materials dispersed throughout. The second component is an inorganic material consisting of nanoparticles of oxides and sulfides supported on clay minerals. This inorganic component has all of the characteristics of an airborne photocatalyst. Nanoparticles of Fe2O3, MnO2 and FeS2 have demonstrated catalytic properties, particularly when they occur in the nanoparticle range, as they do in the subject aerosol materials. These materials have band-gaps that occur in the broad solar spectrum enhancing the photocatalytic adsorption of solar radiation beyond that of the wider band-gap aluminosilicate and titanate materials, which also occur in aerosols. In addition, the materials are acidic and probably are coated with moisture when suspended in air, further enhancing their catalytic ability to crack hydrocarbons and create free radicals

The backbone of the climate network

We propose a method to reconstruct and analyze a complex network from data generated by a spatio-temporal dynamical system, relying on the nonlinear mutual information of time series analysis and betweenness centrality of complex network theory. We show, that this approach reveals a rich internal structure in complex climate networks constructed from reanalysis and model surface air temperature data. Our novel method uncovers peculiar wave-like structures of high energy flow, that we relate to global surface ocean currents. This points to a major role of the oceanic surface circulation in coupling and stabilizing the global temperature field in the long term mean (140 years for the model run and 60 years for reanalysis data). We find that these results cannot be obtained using classical linear methods of multivariate data analysis, and have ensured their robustness by intensive significance testing.Comment: 6 pages, 5 figure

Workplace bullying and interpersonal conflicts: the moderation effect of supervisor’s power

Workplace bullying is considered the final stage of a prolonged conflict where there is a power imbalance between the affected parties and where emotional and relational problems exist. Thus, this study aims to explore the role of perceptions of supervisor’s power bases on the relationship of conflict and bullying at work. A cross-sectional survey study was conducted (N = 211). Results support a moderated-mediation model in which relationship conflict mediates the association between task conflict and workplace bullying, suggesting a conflict escalation process in bullying situations. In addition, establishing personal power bases seems to reduce the intensity of the link between task conflict and relationship conflict and, in turn, workplace bullying, whereas establishing positional power bases was not related to this association. Practical implications for bullying prevention are discussed.info:eu-repo/semantics/acceptedVersio