Capture of field stars by giant interstellar clouds: the formation of moving stellar groups

In the solar neighbourhood, there are moving groups of stars with similar ages and others of stars with heterogeneous ages as the field stars. To explain these facts, we have constructed a simple model of three phases. Phase A: a giant interstellar cloud is uniformly accelerated (or decelerated) with respect to the field stars during a relatively short period of time (10 Myr) and the cloud's mass is uniformly increased; phase B: the acceleration (or deceleration) and mass accretion of the cloud cease. The star formation spreads throughout the cloud, giving origin to stellar groups of similar ages; and phase C: the cloud loses all its gaseous component at a constant rate and in parallel is uniformly decelerated (or accelerated) until reaching the initial velocity of phase A (case 1) or the velocity of the gas cloud remains constant (case 2). Both cases give equivalent results. The system equations for the star motions governed by a time-dependent gravitational potential of the giant cloud and referred to a coordinate system co-moving with the cloud have been solved analytically. We have assumed a homogeneous spheroidal cloud of fixed semi-major axis a=300 pc and of an initial density of 7 at cm^{-3}, with a density increment of 100 per cent and a cloud's velocity variation of 30 km s^{-1}, from the beginning to the end of Phase A. The result is that about 4 per cent of the field stars that are passing within the volume of the cloud at the beginning of phase A is captured. The Sun itself could have been captured by the same cloud that originated the moving groups of the solar neighbourhood.Comment: 13 pages, 15 figure

Automated construction and analysis of political networks via open government and media sources

We present a tool to generate real world political networks from user provided lists of politicians and news sites. Additional output includes visualizations, interactive tools and maps that allow a user to better understand the politicians and their surrounding environments as portrayed by the media. As a case study, we construct a comprehensive list of current Texas politicians, select news sites that convey a spectrum of political viewpoints covering Texas politics, and examine the results. We propose a ”Combined” co-occurrence distance metric to better reflect the relationship between two entities. A topic modeling technique is also proposed as a novel, automated way of labeling communities that exist within a politician’s ”extended” network.Peer ReviewedPostprint (author's final draft

The Struggle to Define Privacy Rights and Liabilities in a Digital World and the Unfortunate Role of Constitutional Standing

Today’s world runs on data. The creation and improvement of technological products and services depend on the exchange of data between people and companies. As people’s lives become more digitized, companies can collect, store, and analyze more data, and in turn, create better technology. But, because consumer data can be very sensitive (think Social Security numbers, GPS location, fingerprint recognition, etc.) this cyclical exchange comes with serious privacy risks; especially in light of more frequent and sophisticated cyberattacks. This creates a face-off between technological growth and privacy rights. While it makes sense that people should be willing to subside some of their privacy in exchange for technological enhancements to things like communication, health, and entertainment, companies should also be doing their best to prevent and respond to cyberattacks. This Note highlights the urgency created by the combination of the digitization of consumer lives, sophisticated hackers, and inadequate data privacy laws. It explains that, because Congress is yet to legislate and the Supreme Court’s findings in Clapper v. Amnesty International USA and Spokeo, Inc. v. Robin created federal circuit splits, data privacy laws are either non-existent or muddled. As a result, it is increasingly difficult for companies or consumers to know their rights, responsibilities, and liabilities in this sphere. Moreover, this Note calls for Congress to establish federal compliance measures with respect to corporate use of consumer data and handling of cyberattacks. However, this Note argues that Congress will continue to remain silent and, therefore, the Supreme Court, by revisiting the constitutional standing issues presented in Clapper and Spokeo, can be the one—for now—to provide much needed guidance with respect to data privacy

Analysis of the Behaviour of Biofuel-Fired Gas Turbine Power Plants

The utilisation of biofuels in gas turbines is a promising alternative to fossil fuels for power generation. It would lead to significant reduction of CO2 emissions using an existing combustion technology, although significant changes seem to be needed and further technological development is necessary. The goal of this work is to perform energy and exergy analyses of the behaviour of gas turbines fired with biogas, ethanol and synthesis gas (bio-syngas), compared with natural gas. The global energy transformation process (i.e. from biomass to electricity) has also been studied. Furthermore, the potential reduction of CO2 emissions attained by the use of biofuels has been determined, considering the restrictions regarding biomass availability. Two different simulation tools have been used to accomplish the aims of this work. The results suggest a high interest and the technical viability of the use of Biomass Integrated Gasification Combined Cycle (BIGCC) systems for large scale power generation