Combustor concepts for aircraft gas turbine low-power emissions reduction

Several combustor concepts were designed and tested to demonstrate significant reductions in aircraft engine idle pollutant emissions. Each concept used a different approach for pollutant reductions: the hot wall combustor employs a thermal barrier coating and impingement cooled liners; the recuperative cooling combustor preheats the air before entering the combustion chamber; and the catalytic converter combustor is composed of a conventional primary zone followed by a catalytic bed for pollutant cleanup. The designs are discussed in detail and test results are presented for a range of aircraft engine idle conditions. The results indicate that ultralow levels of unburned hydrocarbons and carbon monoxide emissions can be achieved

Trends Prediction Using Social Diffusion Models

The importance of the ability of predict trends in social media has been growing rapidly in the past few years with the growing dominance of social media in our everyday's life. Whereas many works focus on the detection of anomalies in networks, there exist little theoretical work on the prediction of the likelihood of anomalous network pattern to globally spread and become "trends". In this work we present an analytic model the social diffusion dynamics of spreading network patterns. Our proposed method is based on information diffusion models, and is capable of predicting future trends based on the analysis of past social interactions between the community's members. We present an analytic lower bound for the probability that emerging trends would successful spread through the network. We demonstrate our model using two comprehensive social datasets - the "Friends and Family" experiment that was held in MIT for over a year, where the complete activity of 140 users was analyzed, and a financial dataset containing the complete activities of over 1.5 million members of the "eToro" social trading community.Comment: 6 Pages + Appendi

Gender and Aztec Life Cycles

Articles in the Handbook take up new research trends and methodologies and current debates. The Handbook articles are divided into seven parts

Insights from the Ancient Word: The use of colonial sources in the study of Aztec society

Includes papers originally presented at the workshop 'Beyond Deconstruction: Engaging Colonial Knowledge', held at King's College, Cambridge, in Sept. 2006, as well as some post-conference papers

Mass murder or religious homicide? Rethinking human sacrifice and interpersonal violence in Aztec society

«Massenmord oder religiöse Tötung? Menschenopfer und interpersonale Gewalt in Aztekischer Gesellschaft überdenken». The Aztec practice of human sacrifice is one of the most sensationalized and bloody cases of mass killing in history, raising essential questions about cultural definitions, personal perceptions and the interrelationship of different forms of violence. Produced as part of a project on the long-term history of interpersonal and mass violence in Latin America, this article assesses the available sources for human sacrifice rates in pre-colonial Tenochtitlan, and lays the groundwork for a comparative analysis of homicide rates, by estimating the number of victims of human sacrifice. Offering an analysis which addresses key themes and structures in the history of violence, this study attempting to reconcile the frequency of 'official' violence with the apparent unacceptability of interpersonal aggression, and interrogates the sensationalism and cultural sensitivities which have often hindered impartial and empathetic studies of the human sacrifice in Aztec society

Adaptive Governance: An Introduction and Implications for Public Policy

Adaptive governance is a concept from institutional theory that deals with the evolution of institutions for the management of shared assets, particularly common pool resources and other forms of natural capital. This paper is the first of a set of four papers on adaptive governance, providing a brief overview of the history of the concept, the distinguishing features of the literature, and key insights provided for economists and policy advisors. We argue that adaptive governance provides an interesting lens for examining the political economy of policy responses akin to the concept of market failure within economics, but applied to wider processes of social learning and collective choice, including collective choices about the scope and structure of institutions that govern lower level choices by individuals and organizations.adaptive governance, public policy, common pool resources, natural resource management, wicked problems, Institutional and Behavioral Economics,

Sampling from the Hardcore Process

Partially Recursive Acceptance Rejection (PRAR) and bounding chains used in conjunction with coupling from the past (CFTP) are two perfect simulation protocols which can be used to sample from a variety of unnormalized target distributions. This paper first examines and then implements these two protocols to sample from the hardcore gas process. We empirically determine the subset of the hardcore process\u27s parameters for which these two algorithms run in polynomial time. Comparing the efficiency of these two algorithms, we find that PRAR runs much faster for small values of the hardcore process\u27s parameter whereas the bounding chain approach is vastly superior for large values of the process\u27s parameter