1,686 research outputs found
Spinarc gas tungsten arc torch holder
Semiautomatic welding torch enables operator to control arc length, torch angle, and spring tension when welding small diameter aluminum tubing. Tungsten is preset for the weld to make arc initiation easier and to eliminate searching for the joint through a dark welding lens
System software for the finite element machine
The Finite Element Machine is an experimental parallel computer developed at Langley Research Center to investigate the application of concurrent processing to structural engineering analysis. This report describes system-level software which has been developed to facilitate use of the machine by applications researchers. The overall software design is outlined, and several important parallel processing issues are discussed in detail, including processor management, communication, synchronization, and input/output. Based on experience using the system, the hardware architecture and software design are critiqued, and areas for further work are suggested
The Area Distribution of Solar Magnetic Bright Points
Magnetic Bright Points (MBPs) are among the smallest observable objects on
the solar photosphere. A combination of G-band observations and numerical
simulations is used to determine their area distribution. An automatic
detection algorithm, employing 1-dimensional intensity profiling, is utilized
to identify these structures in the observed and simulated datasets. Both
distributions peak at an area of 45000 km, with a sharp decrease
towards smaller areas. The distributions conform with log-normal statistics,
which suggests that flux fragmentation dominates over flux convergence.
Radiative magneto-convection simulations indicate an independence in the MBP
area distribution for differing magnetic flux densities. The most commonly
occurring bright point size corresponds to the typical width of intergranular
lanes.Comment: Astrophysical Journal, accepte
The finite element machine: An experiment in parallel processing
The finite element machine is a prototype computer designed to support parallel solutions to structural analysis problems. The hardware architecture and support software for the machine, initial solution algorithms and test applications, and preliminary results are described
The type IIb SN 2008ax: the nature of the progenitor
A source coincident with the position of the type IIb supernova (SN) 2008ax
is identified in pre-explosion Hubble Space Telescope (HST) Wide Field
Planetary Camera 2 observations in three optical filters. We identify and
constrain two possible progenitor systems: (i) a single massive star that lost
most of its hydrogen envelope through radiatively driven mass loss processes,
prior to exploding as a helium-rich Wolf-Rayet star with a residual hydrogen
envelope, and (ii) an interacting binary in a low mass cluster producing a
stripped progenitor. Late time, high resolution observations along with
detailed modelling of the SN will be required to reveal the true nature of this
progenitor star.Comment: 5 pages, 2 figures, resolution of figure 1 reduced, figure 2 revised,
some revision following referee's comments, accepted for publication in MNRAS
letter
Dispatching community-based first responders via text message in violent areas of the Western Cape Province, South Africa
Impulsive Choice and Altruistic Punishment Are Correlated and Increase in Tandem With Serotonin Depletion
Human cooperation may partly depend on the presence of individuals willing to incur personal costs to punish noncooperators. The psychological factors that motivate such 'altruistic punishment' are not fully understood; some have argued that altruistic punishment is a deliberate act of norm enforcement that requires self-control, while others claim that it is an impulsive act driven primarily by emotion. In the current study, we addressed this question by examining the relationship between impulsive choice and altruistic punishment in the ultimatum game. As the neurotransmitter serotonin has been implicated in both impulsive choice and altruistic punishment, we investigated the effects of manipulating serotonin on both measures. Across individuals, impulsive choice and altruistic punishment were correlated and increased following serotonin depletion. These findings imply that altruistic punishment reflects the absence rather than the presence of self control, and suggest that impulsive choice and altruistic punishment share common neural mechanisms
A tidal lung simulation to quantify lung heterogeneity with the Inspired Sinewave Test
We have created a lung simulation to quantify lung heterogeneity from the
results of the inspired sinewave test (IST). The IST is a lung function test
that is non-invasive, non-ionising and does not require patients' cooperation.
A tidal lung simulation is developed to assess this test and also a method is
proposed to calculate lung heterogeneity from IST results. A sensitivity
analysis based on the Morris method and linear regression were applied to
verify and to validate the simulation. Additionally, simulated emphysema and
pulmonary embolism conditions were created using the simulation to assess the
ability of the IST to identify these conditions. Experimental data from five
pigs (pre-injured vs injured) were used for validation. This paper contributes
to the development of the IST. Firstly, our sensitivity analysis reveals that
the IST is highly accurate with an underestimation of about 5% of the simulated
values. Sensitivity analysis suggested that both instability in tidal volume
and extreme expiratory flow coefficients during the test cause random errors in
the IST results. Secondly, the ratios of IST results obtained at two tracer gas
oscillation frequencies can identify lung heterogeneity (ELV60/ELV180 and
Qp60/Qp180). There was dissimilarity between simulated emphysema and pulmonary
embolism (p < 0:0001). In the animal model, the control group had ELV60/ELV180
= 0.58 compared with 0.39 in injured animals (p < 0.0001)
Reconfiguration and regulation of supply chains and HRM in times of economic crisis
This chapter reviews existing evidence on the reconfiguration and regulation of supply chains and employment relations during times of economic crisis. On the one hand, literature has highlighted pressures towards a degradation of standards as firms seek short-term cost advantages. This view is informed by various perspectives from organization studies to political economy but is united by the idea that structural changes in global capitalism drive how firms relate to their suppliers. On the other hand, it has been argued that counter-pressures range from consumer backlashes to the extension of formal and informal regulation across national boundaries. This undeniably heterogeneous literature has common themes suggesting that global forces may be mediated by existing embedded institutional arrangements at transnational, national and local level, and that there are still open-ended possibilities for social action. This chapter synthesizes and evaluates these two streams and identifies agendas for future research
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