Helicopter main-rotor speed effects: A comparison of predicted ranges of detection from the aural detection program ICHIN and the electronic detection program ARCAS

NASA LaRC personnel have conducted a strudy of the predicted acoustic detection ranges associated with reduced helicopter main rotor speeds. This was accomplished by providing identical input information to both the aural detection program ICHIN 6, (I Can Hear It Now, version 6) and the electronic acoustic detection program ARCAS (Assessment of Rotorcraft Detection by Acoustics Sensing). In this study, it was concluded that reducing the main rotor speed of the helicopter by 27 percent reduced both the predicted aural and electronic detection ranges by approximately 50 percent. Additionally, ARCAS was observed to function better with narrowband spectral input than with one-third octave band spectral inputs and the predicted electronic range of acoustic detection is greater than the predicted aural detection range

Helicopter far-field acoustic levels as a function of reduced main-rotor advancing blade-tip Mach number

During the design of a helicopter, the weight, engine, rotor speed, and rotor geometry are given significant attention when considering the specific operations for which the helicopter will be used. However, the noise radiated from the helicopter and its relationship to the design variables is currently not well modeled with only a limited set of full-scale field test data to study. In general, limited field data have shown that reduced main-rotor advancing blade-tip Mach numbers result in reduced far-field noise levels. The status of a recent helicopter noise research project is reviewed. It is designed to provide flight experimental data which may be used to further understand helicopter main-rotor advancing blade-tip Mach number effects on far-field acoustic levels. Preliminary results are presented relative to tests conducted with a Sikorsky S-76A helicopter operating with both the rotor speed and the flight speed as the control variable. The rotor speed was operated within the range of 107 to 90 percent NR at nominal forward speeds of 35, 100, and 155 knots

A technique to investigate space maintenance tasks

Effects of space suit pressurization and weightlessness on performance decrement in space maintenance activit

Welfare can discourage crime more than it discourages work

In recent decades, many governments have attempted to encourage people into work by reducing welfare eligibility. By analyzing the changes in the American Supplemental Security Income program (SSI) policies, Manasi Deshpande and Michael Mueller-Smith find that rather than incentivizing people into employment, removing welfare support instead may push them towards illicit activities to make up for lost income. This increase in criminal activity and subsequent incarceration has large monetary and social costs for society, which effectively cancel out the savings to government from reduced welfare spending

Nonperturbative Effects in Quarkonia Associated with Large Orders in Perturbation Theory

We show that the perturbation series for quarkonia energies diverges at large orders. This results in a perturbative ambiguity in the energy that scales as e^(-1/a*Lambda) where a is the Bohr radius of quarkonium and Lambda is the QCD scale parameter. This ambiguity is associated with a nonperturbative contribution to the energy from distances of order 1/Lambda and greater. This contribution is separate from that of the gluon condensate.Comment: 6 pages, 2 figure

Business, Human Rights, and Corporate Social Responsibility

This presentation is a review of the literature on business and human rights and Corporate Social Responsibility. Globalization has lead to human rights and business being a combined topic. The United Nations and other countries have began to recognize human rights with labor regulations due to the misconduct in applied legislation. Our research focuses on the country of Myanmar also known as Burma. The United States in particular has had a long history working with Myanmar. During the 2000\u27s American companies have been developing strict labor policies. Through research, companies discovered that implementing business policies and labor regulations programs increase the community\u27s development. A case study shows how Coca-Cola worked in Myanmar to form a strategic plan assisting Myanmar\u27s community. Through corporate responsibility and labor solidarity, companies can work in high-risk environments and achieve positive outcomes

Estimating the numbers of malaria infections in blood samples using high-resolution genotyping data

People living in endemic areas often habour several malaria infections at once. High-resolution genotyping can distinguish between infections by detecting the presence of different alleles at a polymorphic locus. However the number of infections may not be accurately counted since parasites from multiple infections may carry the same allele. We use simulation to determine the circumstances under which the number of observed genotypes are likely to be substantially less than the number of infections present and investigate the performance of two methods for estimating the numbers of infections from high-resolution genotyping data.THE SIMULATIONS SUGGEST THAT THE PROBLEM IS NOT SUBSTANTIAL IN MOST DATASETS: the disparity between the mean numbers of infections and of observed genotypes was small when there was 20 or more alleles, 20 or more blood samples, a mean number of infections of 6 or less and where the frequency of the most common allele was no greater than 20%. The issue of multiple infections carrying the same allele is unlikely to be a major component of the errors in PCR-based genotyping.Simulations also showed that, with heterogeneity in allele frequencies, the observed frequencies are not a good approximation of the true allele frequencies. The first method that we proposed to estimate the numbers of infections assumes that they are a good approximation and hence did poorly in the presence of heterogeneity. In contrast, the second method by Li et al estimates both the numbers of infections and the true allele frequencies simultaneously and produced accurate estimates of the mean number of infections

Governance from below in Bolivia: a theory of local government with two empirical tests

This article examines decentralization through the lens of the local dynamics it unleashed in the much-noted case of Bolivia. It argues that the national effects of decentralization are largely the sum of its local-level effects. To understand decentralization, therefore, we must first understand how local government works. The article explores the deep economic and institutional determinants of government quality in two extremes of municipal performance. From this it derives a model of local government responsiveness as the product of political openness and substantive competition. The quality of local politics, in turn, emerges endogenously as the joint product of the lobbying and political engagement of local firms and interests and the organizational density and ability of civil society. The analysis tests the theory's predictions on a database containing all Bolivian municipalities. The theory proves robust. The combined methodology provides a higher-order empirical rigor than either approach can alone