SNR-calibrated Type Ia supernova models

Current Type Ia supernova (SN Ia) models can reproduce most visible+IR + UV observations. In the X-ray band, the determination of elemental abundance ratios in supernova remnants (SNRs) through their spectra has reached enough precision to constrain SN Ia models. Martínez-Rodríguez et al have shown that the Ca/S mass ratio in SNRs cannot be reproduced with the standard nuclear reaction rates for a wide variety of SN Ia models, and suggested that the 12C+16O reaction rate could be overestimated by a factor as high as ten. We show that the same Ca/S ratio can be obtained by simultaneously varying the rates of the reactions 12C + 16O, 12C + 12C, 16O + 16O, and 16O(¿, a)12C within the reported uncertainties. We also show that the yields of the main products of SN Ia nucleosynthesis do not depend on the details of which rates are modified, but can be parametrized by an observational quantity such as Ca/S. Using this SNR-calibrated approach, we then proceed to compute a new set of SN Ia models and nucleosynthesis for both Chandrasekhar and sub-Chandrasekhar mass progenitors with a 1D hydrodynamics and nucleosynthesis code. We discuss the nucleosynthesis of the models as a function of progenitor metallicity, mass, and deflagration-to-detonation transition density. The yields of each model are almost independent on the reaction rates modified for a common Ca/S ratio.Peer ReviewedPostprint (author's final draft

Coupled Flow-Geomechanics Numerical Investigation of Microearthquakes and Planar Fracture Propagation in the Barnett Shale

The purpose of this study is to investigate the effects of hydraulic fracturing stimulation for development of shale gas reservoirs. Particularly, the study considers the vertical planar fracture propagation and induced seismicity during hydraulic fracturing operations in the Barnett Shale. To this end, a sequentially implicit coupled-flow-geomechanics-geophysical simulator is used to generate a realistic model and to study the effects and potential issues surrounding hydraulic fracturing stimulating vertical and horizontal wells in the Barnett Shale. In addition, a sensitivity analysis is performed on the model to determine how the uncertainty of the model outputs can be apportioned to different sources of uncertainty in its inputs. From the results of the model combined with the literature, we obtain stable fracture propagation, having the limited vertical extent of the fractures. Furthermore, the model suggests that vertical extent of fractures is limited due to rock strength heterogeneity and variations of the stress field, while failure around cementing wells might be possible. Additionally, the magnitude of modelled the micro-earthquakes generated during hydraulic fracturing stimulation were not large enough to warrant safety concerns regarding seismicity, unless faults exist nearby. Finally, based on the outputs of the model, it is possible to couple a sequential flow-geomechanics simulator to model micro-earthquakes, fracture propagation, and stimulated reservoir area

Passage of the State and the Law to Postmodernity

The present article seeks to explore the social genesis that he/she came giving origin to the implementation and constitution of what is known as the neoliberal field and neoinstitucional like novel formulas of global regulation of the social relationships of production of the capitalism globalization in our days. The hypothesis that defends in these lines is that these fields are the fruit of the exhaustion that suffered the Taylorista-Fordista-Keynesian pattern characteristic of the compound number State of Well-being, due to the nature of the social fights that you/they were developed inside that context. The general objective that one wants to show in the argument is that the type of Right associated to the State of Well-being is intimately associated to the theses that it has more than enough the same one Max Weber it developed but that in our days that type of rationality more and more it spreads to lack sense. The article wants to be introduced in the contemporary discussion on the character and meaning of the Right in the society of the capitalism globalization to register in the theoretical and political plane of its regulation nature and subordination or of its nature emancipator in the breast of the social movement

Towards Sustainability: Photochemical and electrochemical processes applied for environmental protection

In the last century, public policy around the globe was mainly focused on economic growth leaving out of this perspective, social concerns and the environment detriment that this merely economic approach was causing. It was until the last quarter of the 20th century that people started to be aware of the growing poverty and of the jeopardy of the planet as a result of human being activities. In consequence, the concept of sustainable development emerged in the United Nations as a call to all countries to integrate economic growth with social needs and environmental protection, in such a way that our activities as earth inhabitants stopped compromising the quality of life and needs satisfaction of future generations