2,318 research outputs found
Paper Session III-A - Ergonomic Considerations in Launch Vehicle Design and Processing for Operational Efficiency
Ergonomics is the science of fitting the environment and activities to the capabilities, dimensions, and needs of people. Ergonomic knowledge and principles are applied to adapt working conditions to the physical, psychological, and social nature of the person. There have been numerous launch operations studies performed concerning processing operations at the Kennedy Space Center (KSC). These studies have not, to a significant extent, considered ergonomic principles in launch vehicle design and processing as a means for achieving the goals of operational efficiency. Many launch vehicle design and processing goals or objectives have been proposed to increase the operational efficiency of current systems, or to improve the operational efficiency of future systems over that experienced by current systems. Future proposed design or processing objectives may not take ergonomic principles and guidelines into consideration. A few of the launch vehicle design or processing objectives currently under consideration and their associated concerns, from an ergonomic aspect, are:
• Paperless work documentation system and health related concerns with visual display terminal (VDT) and personal computer (PC) use.
• Automated vehicle health management and built-in test equipment (BITE) causing troubles with human reliability and cognition associated with human-machine systems.
• Hazardous operations scheduled for third-shift and problems associated with night-worker health.
This examinational paper is intended to inform the reader on some of the ergonomic principles that should be considered in the design and processing of launch vehicles for operational efficiency
Nonintegrability, Chaos, and Complexity
Two-dimensional driven dissipative flows are generally integrable via a
conservation law that is singular at equilibria. Nonintegrable dynamical
systems are confined to n*3 dimensions. Even driven-dissipative deterministic
dynamical systems that are critical, chaotic or complex have n-1 local
time-independent conservation laws that can be used to simplify the geometric
picture of the flow over as many consecutive time intervals as one likes. Those
conserevation laws generally have either branch cuts, phase singularities, or
both. The consequence of the existence of singular conservation laws for
experimental data analysis, and also for the search for scale-invariant
critical states via uncontrolled approximations in deterministic dynamical
systems, is discussed. Finally, the expectation of ubiquity of scaling laws and
universality classes in dynamics is contrasted with the possibility that the
most interesting dynamics in nature may be nonscaling, nonuniversal, and to
some degree computationally complex
Statistical Mechanics of Quantum-Classical Systems with Holonomic Constraints
The statistical mechanics of quantum-classical systems with holonomic
constraints is formulated rigorously by unifying the classical Dirac bracket
and the quantum-classical bracket in matrix form.
The resulting Dirac quantum-classical theory, which conserves the holonomic
constraints exactly, is then used to formulate time evolution and statistical
mechanics. The correct momentum-jump approximation for constrained system
arises naturally from this formalism. Finally, in analogy with what was found
in the classical case, it is shown that the rigorous linear response function
of constrained quantum-classical systems contains non-trivial additional terms
which are absent in the response of unconstrained systems.Comment: Submitted to Journal of Chemical Physic
Toward a constructivist model of radicalization and deradicalization: a conceptual and methodological proposal.
© 2019 Feixas and Winter.This article identifies common features of existing models of radicalization and deradicalization, such as the transition from uncertainty to certainty, before integrating these in a model based upon personal construct theory. It is proposed that the personal construct concepts of validation and invalidation are particularly relevant to processes of identity change such as radicalization and deradicalization. Thus, it is argued that radicalization occurs when major invalidation of an individual’s construing is followed by the development of a new radicalized view of the world that provides a turning point in his or her sense of identity and a more structured and certain view of the world. There is likely to be seeking out of validation for this view in interactions with others who share similar views or by extorting evidence for the individual’s radical constructions. These constructions are likely to involve extreme negative views of another group, by contrast to members of which, and possibly by taking extreme action against this group, the individual’s new self-construction may become further defined. These same processes can be seen to operate in deradicalization, and it will therefore be argued that the model has implications for the development of deradicalization programs. A further advantage of the model is that it has an associated personal construct methodology, particularly repertory grid technique, that may be used to investigate processes of radicalization and deradicalization. As illustrations of such investigations, results will be summarized from a repertory grid study of Salafist Muslims in Tunisia, some of whom had returned from fighting in Syria, and an analysis of the writings of the Norwegian mass murderer Anders Breivik. The findings of these investigations are argued to be consistent with the personal construct model of radicalization and deradicalization.Peer reviewe
Geomagnetically Induced Currents in the Irish Power Network during Geomagnetic Storms
Geomagnetically induced currents (GICs) are a well-known terrestrial space
weather hazard. They occur in power transmission networks and are known to have
adverse effects in both high and mid-latitude countries. Here, we study GICs in
the Irish power transmission network (geomagnetic latitude 54.7--58.5
N) during five geomagnetic storms (06-07 March 2016, 20-21 December 2015, 17-18
March 2015, 29-31 October 2003 and 13-14 March 1989). We simulate electric
fields using a plane wave method together with two ground resistivity models,
one of which is derived from magnetotelluric measurements (MT model). We then
calculate GICs in the 220, 275 and 400~kV transmission network. During the
largest of the storm periods studied, the peak electric field was calculated to
be as large as 3.8~V~km\textsuperscript{-1}, with associated GICs of up to 23~A
using our MT model. Using our homogenous resistivity model, those peak values
were 1.46~V~km\textsuperscript{-1} and 25.8~A. We find that three 400 and
275~kV substations are the most likely locations for the Irish transformers to
experience large GICs.Comment: 14 pages, 11 Figures, 4 Table
Geomagnetic conditions in Ireland During the St. Patrick's Day 2015 Storm
<p>Poster at UK National Astronomy Meeting in Llandudno, Wales on July 5-9, 2015 (www.nam2015.org)</p>
<p>Abstract:</p>
<p>Two coronal mass ejections were launched in quick succession from the Sun on March 15, 2015. They impacted the Earth's magnetosphere two days later on St. Patrick's Day (March 17), resulting in a geomagnetic storm with a planetary K-Index of 8.</p>
<p>Magnetic variations were measured across a recently deployed magnetometer network in Ireland and geoelectric fields were measured at a site in Co. Leitrim (magnetic latitude 57.08°). A local K-index maximum of 7 was calculated at Birr, Co. Offaly (magnetic latitude 55.97), while the aurora</p>
<p>borealis accompanying the geomagnetic storm was visible as far south as Co. Waterford (magnetic latitude 55.13°).</p>
<p>The British Geological Survey thin-sheet surface electric field model was used together with our magnetometer measurements to calculate electric fields and geomagnetically induced currents (GICs) in the Irish power grid.</p>
<p>Although it was one of the most magnetically disturbed days in a decade, with dB/dt reaching ~50 nT/min, the peak GIC level estimated in the Irish power grid was ~10 Amps. Note, no adverse effects were reported in the Irish power grid demonstrating its resilience to geomagnetic storms of this magnitude.</p
Effects of Multi-Surface Modification on Curie temperature of ferroelectric films
Within the framework of mean field theory, we study the effects of
multi-surface modification on Curie temperature of ferroelectric films using
the transverse Ising model. The general nonlinear equations for Curie
temperature of multi-surface ferroelectric films with arbitrary exchange
constants and transverse fields are derived by the transfer matrix method. As
an example, we consider a film consisting of top surface layers, bulk layers
and bottom surface layers. Two types of surface modifications, modifications of
a surface exchange constant and a surface transverse field are taken into
account. The dependence of Curie temperature on the surface layer numbers, bulk
layer numbers, surface exchange constants, surface transverse fields and bulk
transverse fields is discussed.Comment: 11 pages, 5 figure
CAMKII as a therapeutic target for growth factor-induced retinal and choroidal neovascularisation
This study was supported by grants from the British Heart Foundation (PG/11/99/29207 and PG/11/94/29169), Fight for Sight, UK (1387/88), Health & Social Care R&D Division, Northern Ireland (STL/4748/13) and the Medical Research Council (MC_PC_15026). We would like to thank Gordon Revolta for excellent assistance with colony management and genotyping.Peer reviewedPublisher PD
Insights from Amphioxus into the Evolution of Vertebrate Cartilage
Central to the story of vertebrate evolution is the origin of the vertebrate head, a problem difficult to approach using paleontology and comparative morphology due to a lack of unambiguous intermediate forms. Embryologically, much of the vertebrate head is derived from two ectodermal tissues, the neural crest and cranial placodes. Recent work in protochordates suggests the first chordates possessed migratory neural tube cells with some features of neural crest cells. However, it is unclear how and when these cells acquired the ability to form cellular cartilage, a cell type unique to vertebrates. It has been variously proposed that the neural crest acquired chondrogenic ability by recruiting proto-chondrogenic gene programs deployed in the neural tube, pharynx, and notochord. To test these hypotheses we examined the expression of 11 amphioxus orthologs of genes involved in neural crest chondrogenesis. Consistent with cellular cartilage as a vertebrate novelty, we find that no single amphioxus tissue co-expresses all or most of these genes. However, most are variously co-expressed in mesodermal derivatives. Our results suggest that neural crest-derived cartilage evolved by serial cooption of genes which functioned primitively in mesoderm
Determinants of Agricultural Pesticide Concentrations in Carpet Dust
Background: Residential proximity to agricultural pesticide applications has been used as a surrogate for exposure in epidemiologic studies, although little is known about the relationship with levels of pesticides in homes
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