2,951 research outputs found

    Foam composite structures

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    The need to include fire resistant foams into state of the art aircraft interior paneling to increase passenger safety in aircraft fires was studied. Present efforts were directed toward mechanical and fire testing of panels with foam inclusions. Skinned foam filled honeycomb and PBI structural foams were the two constructions investigated with attention being directed toward weight/performance/cost trade-off. All of the new panels demonstrated improved performance in fire and some were lighter weight but not as strong as the presently used paneling. Continued efforts should result in improved paneling for passenger safety. In particular the simple partial filling (fire side) of state-of-the-art honeycomb with fire resistant foams with little sacrifice in weight would result in panels with increased fire resistance. More important may be the retarded rate of toxic gas evolution in the fire due to the protection of the honeycomb by the foam

    We Could, but Should We? Ethical Considerations for Providing Access to GeoCities and Other Historical Digital Collections

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    We live in an era in which the ways that we can make sense of our past are evolving as more artifacts from that past become digital. At the same time, the responsibilities of traditional gatekeepers who have negotiated the ethics of historical data collection and use, such as librarians and archivists, are increasingly being sidelined by the system builders who decide whether and how to provide access to historical digital collections, often without sufficient reflection on the ethical issues at hand. It is our aim to better prepare system builders to grapple with these issues. This paper focuses discussions around one such digital collection from the dawn of the web, asking what sorts of analyses can and should be conducted on archival copies of the GeoCities web hosting platform that dates to 1994.This research was supported by the Natural Sciences and Engineering Research Council of Canada, the Social Sciences and Humanities Research Council of Canada, the US National Science Foundation (grants 1618695 and 1704369), the Andrew W. Mellon Foundation, Start Smart Labs, and Compute Canada

    The promise and limits of private standards to reduce greenhouse gas emissions from shipping

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    This article examines private standards that aim to mitigate greenhouse gas (GHG) emissions in shipping. These have emerged against a backdrop of regulatory inertia and the exclusion of international shipping from the Paris Climate Change Agreement. They are a product of complex governance arrangements and they have addressed areas of market failure that have held back fuel efficiency advances that are made possible by technological innovations. These private standards hold considerable promise but suffer to different degrees from certain weaknesses, notably a lack of transparency, a low level of ambition and concerns about data reliability. This article examines these deficiencies together with the reasons for them, and assesses the role that law could play in addressing them. It argues that the conditions may be present for the mitigation of shipping’s GHG emissions to become a site of ‘hybrid’ governance, combining private standards and state/supra-state law in a productive way

    Transmission Planning Process and Opportunities for Utility-Scale Solar Engagement within the Western Electricity Coordinating Council (WECC)

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    This report is a primer for solar developers who wish to engage directly in expediting the regulatory process and removing market barriers related to policy and planning. Market barriers unrelated to technology often limit the expansion of utility-scale solar power, even in areas with exceptional resource potential. Many of these non-technical barriers have to do with policy, regulation, and planning, and hardly ever do they resolve themselves in a timely fashion. In most cases, pre-emptive intervention by interested stakeholders is the easiest way to remove/address such barriers, but it requires knowing how to navigate the institutional waters of the relevant agencies and boards. This report is a primer for solar developers who wish to engage directly in expediting the regulatory process and removing market barriers related to policy and planning. It focuses on the Western Interconnection (WI), primarily because the quality of solar resources in the Southwest makes utility-scale concentrating solar power (CSP) and photovoltaics (PV) economically feasible, and because the relevant institutions have evolved in a way that has opened up opportunities for removing non-technical market barriers. Developers will find in this report a high-level field manual to identify the venues for mitigating and possibly eliminating systemic market obstacles and ensuring that the economic playing field is reasonably level. Project-specific issues such as siting for transmission and generation resources are beyond the scope of this report. Instead, the aim is to examine issues that pervasively affect all utility-scale PV and CSP in the region regardless of where the project may be. While the focus is on the WI, many of the institutions described here also have their counterparts in the Eastern and the Texas interconnections. Specifically, this report suggests a number of critical engagement points relating to generation and transmission planning

    Distinct phosphorylation clusters determines the signalling outcome of the free fatty acid receptor FFA4/GPR120

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    It is established that long-chain free fatty acids including ω-3 fatty acids mediate an array of biological responses through members of the free fatty acid receptor family, which includes FFA4. However, the signalling mechanisms and modes of regulation of this receptor class remain unclear. Here we employ mass spectrometry to determine that phosphorylation of mouse (m)FFAR4 occurs at five serine and threonine residues clustered in two separable regions of the C terminal tail, designated cluster 1 (Thr347, Thr349 and Ser350) and cluster 2 (Ser357 and Ser361). Mutation of these phospho-acceptor sites to alanine completely prevented phosphorylation of mFFA4 but did not limit receptor coupling to ERK1/2 activation. Rather an inhibitor of Gq/11 proteins completely prevented receptor signalling to ERK1/2. In contrast, the recruitment of arrestin 3, receptor internalization and activation of Akt were regulated by mFFA4 phosphorylation. The analysis of mFFA4 phosphorylation-dependent signalling was extended further by selective mutations of the phospho-acceptor sites. Mutations within cluster 2 did not affect agonist activation of Akt but instead significantly compromised receptor internalization and arrestin 3 recruitment. Distinctly, mutation of the phospho-acceptor sites within cluster 1 had no effect on receptor internalization and a less extensive effect on arrestin 3 recruitment, but significantly uncoupled the receptor from Akt activation. These unique observations define differential effects on signalling mediated by phosphorylation at distinct locations. This hallmark feature supports the possibility that the signalling outcome of mFFA4 activation can be determined by the pattern of phosphorylation (phosphorylation barcode) at the C-terminus of the receptor

    Energy system development pathways for Ethiopia: Final project report

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    This report forms a deliverable of the Energy System Development Pathways for Ethiopia (PATHWAYS) project. The project explored pathways for Ethiopia’s electricity system to 2065 with the use of open-source energy system models, and developed local capacity to use and build on those models for the country’s energy planning and policy decision-support. A participatory methodology was adopted, which engaged local experts and stakeholders in the co-creation of knowledge, through multiple and mixed methods of inquiry typically adopted in fields of engineering and the social sciences. Some of these engagement activities included workshops and interviews that drew upon local expertise to shape the narratives and boundaries on the possible futures for Ethiopia’s electricity system, as well as a household survey on energy consumer behaviour. In addition, capacity development workshops were conducted; training students, academics, and staff of the government, not-for-profit and the private sector on the use of the Open-Source Energy System Modelling framework (OSeMOSYS). This report provides the synthesised findings of the project and highlights ways of building on its activities

    Observations of the Sensitivity of Beam Attenuation to Particle Size in a Coastal Bottom Boundary Layer

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    The goal of this study was to test the hypothesis that the aggregated state of natural marine particles constrains the sensitivity of optical beam attenuation to particle size. An instrumented bottom tripod was deployed at the 12-m node of the Martha\u27s Vineyard Coastal Observatory to monitor particle size distributions, particle size-versus-settling-velocity relationships, and the beam attenuation coefficient (c(p)) in the bottom boundary layer in September 2007. An automated in situ filtration system on the tripod collected 24 direct estimates of suspended particulate mass (SPM) during each of five deployments. On a sampling interval of 5 min, data from a Sequoia Scientific LISST 100x Type B were merged with data from a digital floc camera to generate suspended particle volume size distributions spanning diameters from approximately 2 mu m to 4 cm. Diameter-dependent densities were calculated from size-versus-settling-velocity data, allowing conversion of the volume size distributions to mass distributions, which were used to estimate SPM every 5 min. Estimated SPM and measured c(p) from the LISST 100x were linearly correlated throughout the experiment, despite wide variations in particle size. The slope of the line, which is the ratio of c(p) to SPM, was 0.22 g m(-2). Individual estimates of c(p):SPM were between 0.2 and 0.4 g m(-2) for volumetric median particle diameters ranging from 10 to 150 mu m. The wide range of values in c(p):SPM in the literature likely results from three factors capable of producing factor-of-two variability in the ratio: particle size, particle composition, and the finite acceptance angle of commercial beam-transmissometers

    Observations of the Sensitivity of Beam Attenuation to Particle Size in a Coastal Bottom Boundary Layer

    Get PDF
    The goal of this study was to test the hypothesis that the aggregated state of natural marine particles constrains the sensitivity of optical beam attenuation to particle size. An instrumented bottom tripod was deployed at the 12-m node of the Martha\u27s Vineyard Coastal Observatory to monitor particle size distributions, particle size-versus-settling-velocity relationships, and the beam attenuation coefficient (c(p)) in the bottom boundary layer in September 2007. An automated in situ filtration system on the tripod collected 24 direct estimates of suspended particulate mass (SPM) during each of five deployments. On a sampling interval of 5 min, data from a Sequoia Scientific LISST 100x Type B were merged with data from a digital floc camera to generate suspended particle volume size distributions spanning diameters from approximately 2 mu m to 4 cm. Diameter-dependent densities were calculated from size-versus-settling-velocity data, allowing conversion of the volume size distributions to mass distributions, which were used to estimate SPM every 5 min. Estimated SPM and measured c(p) from the LISST 100x were linearly correlated throughout the experiment, despite wide variations in particle size. The slope of the line, which is the ratio of c(p) to SPM, was 0.22 g m(-2). Individual estimates of c(p):SPM were between 0.2 and 0.4 g m(-2) for volumetric median particle diameters ranging from 10 to 150 mu m. The wide range of values in c(p):SPM in the literature likely results from three factors capable of producing factor-of-two variability in the ratio: particle size, particle composition, and the finite acceptance angle of commercial beam-transmissometers
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