55,649 research outputs found
Auralization of Air Vehicle Noise for Community Noise Assessment
This paper serves as an introduction to air vehicle noise auralization and documents the current state-of-the-art. Auralization of flyover noise considers the source, path, and receiver as part of a time marching simulation. Two approaches are offered; a time domain approach performs synthesis followed by propagation, while a frequency domain approach performs propagation followed by synthesis. Source noise description methods are offered for isolated and installed propulsion system and airframe noise sources for a wide range of air vehicles. Methods for synthesis of broadband, discrete tones, steady and unsteady periodic, and a periodic sources are presented, and propagation methods and receiver considerations are discussed. Auralizations applied to vehicles ranging from large transport aircraft to small unmanned aerial systems demonstrate current capabilities
Rapid surfactant-free synthesis of Mg(OH)2 nanoplates and pseudomorphic dehydration to MgO
Magnesium hydroxide nanoplates ca. 50 nm in thickness can be prepared over minute timescales via hydrothermal synthesis in a multimode cavity (MMC) microwave reactor. This approach allows ca. 1 g of single-phase Mg(OH)2 to be synthesised in under 3 minutes without the requirement of surfactants or non-aqueous solvents. The hydroxide nanomaterial dehydrates at temperatures >200 K below that of the equivalent bulk material and can be utilised as a precursor for the pseudomorphic synthesis of nanoplates of MgO as investigated by TG-DTA-MS, XRD and SEM measurements. Equally, the pseudomorphic synthesis can be performed by irradiating the Mg(OH)2 nanomaterial with microwaves for 6 minutes to produce single phase MgO
Extended Inclusive Fitness Theory bridges Economics and Biology through a common understanding of Social Synergy
Inclusive Fitness Theory (IFT) was proposed half a century ago by W.D.
Hamilton to explain the emergence and maintenance of cooperation between
individuals that allows the existence of society. Contemporary evolutionary
ecology identified several factors that increase inclusive fitness, in addition
to kin-selection, such as assortation or homophily, and social synergies
triggered by cooperation. Here we propose an Extend Inclusive Fitness Theory
(EIFT) that includes in the fitness calculation all direct and indirect
benefits an agent obtains by its own actions, and through interactions with kin
and with genetically unrelated individuals. This formulation focuses on the
sustainable cost/benefit threshold ratio of cooperation and on the probability
of agents sharing mutually compatible memes or genes. This broader description
of the nature of social dynamics allows to compare the evolution of cooperation
among kin and non-kin, intra- and inter-specific cooperation, co-evolution, the
emergence of symbioses, of social synergies, and the emergence of division of
labor. EIFT promotes interdisciplinary cross fertilization of ideas by allowing
to describe the role for division of labor in the emergence of social
synergies, providing an integrated framework for the study of both, biological
evolution of social behavior and economic market dynamics.Comment: Bioeconomics, Synergy, Complexit
3D-printed devices for continuous-flow organic chemistry
We present a study in which the versatility of 3D-printing is combined with the processing advantages of flow chemistry for the synthesis of organic compounds. Robust and inexpensive 3D-printed reactionware devices are easily connected using standard fittings resulting in complex, custom-made flow systems, including multiple reactors in a series with in-line, real-time analysis using an ATR-IR flow cell. As a proof of concept, we utilized two types of organic reactions, imine syntheses and imine reductions, to show how different reactor configurations and substrates give different products
Needs and challenges for assessing the environmental impacts of engineered nanomaterials (ENMs).
The potential environmental impact of nanomaterials is a critical concern and the ability to assess these potential impacts is top priority for the progress of sustainable nanotechnology. Risk assessment tools are needed to enable decision makers to rapidly assess the potential risks that may be imposed by engineered nanomaterials (ENMs), particularly when confronted by the reality of limited hazard or exposure data. In this review, we examine a range of available risk assessment frameworks considering the contexts in which different stakeholders may need to assess the potential environmental impacts of ENMs. Assessment frameworks and tools that are suitable for the different decision analysis scenarios are then identified. In addition, we identify the gaps that currently exist between the needs of decision makers, for a range of decision scenarios, and the abilities of present frameworks and tools to meet those needs
A review of methods for addressing components of interventions in meta-analysis
Many healthcare interventions are complex, consisting of multiple, possibly interacting, components. Several methodological articles addressing complex interventions in the metaanalytical context have been published. We hereby provide an overview of methods used to evaluate the effects of complex interventions with meta-analytical models. We summarized the methodology, highlighted new developments, and described the benefits, drawbacks, and potential challenges of each identified method. We expect meta-analytical methods focusing on components of several multicomponent interventions to become increasingly popular due to recently developed, easy-to-use, software tools that can be used to conduct the relevant analyses. The different meta-analytical methods are illustrated through two examples comparing psychotherapies for panic disorder. Copyright
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