181 research outputs found
Dirty Laundry in Manila: Comparing Resource Consumption Practices for Individual and Shared Laundering
© 2017 by Yale University Changing lifestyles in developing and emerging economies entail a shift in technology use, everyday practices, and resource consumption. It is important to understand the sustainability consequences of these changes and the potential for policy to guide practices toward more sustainable lifestyles. In this study, we investigate laundry practices in the City of Manila, the Philippines, and compare the resources consumed in three different modes of laundering. We examine (1) traditional washing by hand, (2) washing by machine at home, and (3) using a laundry service. In addition to comparing the consumption of water, energy, and detergents, we also examine the social aspects of laundering using the lens of social practice theory. We use empirical data gathered in interviews with laundry service operators and people laundering at home to undertake qualitative and quantitative analyses of laundry practices and resource consumption. We find that hand washing uses the least water and energy, but large quantities of detergents. Machine washing and laundry services are comparable for water consumption, but energy use is much higher for services as they use dryers. Social changes, such as an increase in work available for women and the nature of future housing, are likely to influence the dominance of either shared or individual laundering methods. These findings illustrate the social complexity of transitions to product-service systems and the interdependencies between their social and environmental impacts
A Theoretical Light-Curve Model for the Recurrent Nova V394 Coronae Austrinae
A theoretical light curve for the 1987 outburst of V394 Coronae Austrinae
(V394 CrA) is modeled to obtain various physical parameters of this recurrent
nova. We then apply the same set of parametersto a quiescent phase and confirm
that these parameters give a unified picture of the binary. The early visual
light curve (1-10 days after the optical maximum) is well reproduced by a
thermonuclear runaway model on a very massive WD close to the Chandrasekhar
limit (1.37 +- 0.01 M_sun). The ensuing plateau phase (10-30 days) is also
reproduced by the combination of a slightly irradiated MS and a fully
irradiated flaring-up disk with a radius ~1.4 times the Roche lobe size. The
best fit parameters are the WD mass 1.37 M_sun, the companion mass 1.5 M_sun
(0.8-2.0 M_sun is acceptable), the inclination angle of the orbit i~65-68
degree, and the flaring-up rim ~0.30 times the disk radius. The envelope mass
at the optical peak is estimated to be ~6 x 10^{-6} M_sun, which indicates an
average mass accretion rate of 1.5 x 10^{-7} M_sun yr^{-1} during the quiescent
phase between the 1949 and 1987 outbursts. In the quiescent phase, the observed
light curve can be reproduced with a disk size of 0.7 times the Roche lobe size
and a rather slim thickness of 0.05 times the accretion disk size at the rim.
About 0.5 mag sinusoidal variation of the light curve requires the mass
accretion rate higher than ~1.0 x 10^{-7} M_sun yr^{-1}, which is consistent
with the above estimation from the 1987 outburst. These newly obtained
quantities are exactly the same as those predicted in a new progenitor model of
Type Ia supernovae.Comment: 9 pages including 4 figures, to appear in the Astrophysical Journal,
Part
Changes in the long term intensity variations in Cyg X-2 and LMC X-3
We report the detection of changes in the long-term intensity variations in
two X-ray binaries, Cyg X-2 and LMC X-3. In this work, we have used the
long-term light curves obtained with the All-Sky Monitors (ASMs) of the Rossi
X-Ray Timing Explorer (RXTE), Ginga, Ariel 5, and Vela 5B and the scanning
modulation collimator of HEAO 1. It is found that in the light curves of both
the sources, obtained with these instruments at various times over the last 30
years, more than one periodic or quasi-periodic component is always present.
The multiple prominent peaks in the periodograms have frequencies unrelated to
each other. In Cyg X-2, RXTE-ASM data show strong peaks at 40.4 and 68.8 days,
and Ginga-ASM data show strong peaks at 53.7 and 61.3 days. Multiple peaks are
also observed in LMC X-3. The various strong peaks in the periodograms of LMC
X-3 appear at 104, 169, and 216 days (observed with RXTE-ASM) and 105, 214, and
328 days (observed with Ginga-ASM). The present results, when compared with the
earlier observations of periodicities in these two systems, demonstrate the
absence of any stable long period. The 78 day periodicity detected earlier in
Cyg X-2 was probably due to the short time base in the RXTE data that were
used, and the periodicity of 198 days in LMC X-3 was due to a relatively short
duration of observation with HEAO 1.Comment: 11 pages, 7 postscript figures include
Skin conductance variability in ICU patients: an observational study of the relation to pain and Motor Activity Assessment Scale level
Analyzing X-Ray Pulsar Profiles: Geometry and Beam Pattern of Her X-1
We report on our analysis of a large sample of energy dependent pulse
profiles of the X-ray binary pulsar Hercules X-1. We find that all data are
compatible with the assumption of a slightly distorted magnetic dipole field as
sole cause of the asymmetry of the observed pulse profiles. Further the
analysis provides evidence that the emission from both poles is equal. We
determine an angle of 20 deg between the rotation axis and the local magnetic
axis. One pole has an offset of 5 deg from the antipodal position of the other
pole. The beam pattern shows structures that can be interpreted as pencil- and
fan-beam configurations. Since no assumptions on the polar emission are made,
the results can be compared with various emission models. A comparison of
results obtained from pulse profiles of different phases of the 35-day cycle
indicates different attenuation of the radiation from the poles being
responsible for the change of the pulse shape during the main-on state. These
results also suggest the resolution of an ambiguity within a previous analysis
of pulse profiles of Cen X-3, leading to a unique result for the beam pattern
of this pulsar as well. The analysis of pulse profiles of the short-on state
indicates that a large fraction of the radiation cannot be attributed to the
direct emission from the poles. We give a consistent explanation of both the
evolution of the pulse profile and the spectral changes with the 35-day cycle
in terms of a warped precessing accretion disk.Comment: 24 pages, 12 figures. To appear in ApJ 529 #2, 1 Feb 200
On the tilting of protostellar disks by resonant tidal effects
We consider the dynamics of a protostellar disk surrounding a star in a
circular-orbit binary system. Our aim is to determine whether, if the disk is
initially tilted with respect to the plane of the binary orbit, the inclination
of the system will increase or decrease with time. The problem is formulated in
the binary frame in which the tidal potential of the companion star is static.
We consider a steady, flat disk that is aligned with the binary plane and
investigate its linear stability with respect to tilting or warping
perturbations. The dynamics is controlled by the competing effects of the m=0
and m=2 azimuthal Fourier components of the tidal potential. In the presence of
dissipation, the m=0 component causes alignment of the system, while the m=2
component has the opposite tendency. We find that disks that are sufficiently
large, in particular those that extend to their tidal truncation radii, are
generally stable and will therefore tend to alignment with the binary plane on
a time-scale comparable to that found in previous studies. However, the effect
of the m=2 component is enhanced in the vicinity of resonances where the outer
radius of the disk is such that the natural frequency of a global bending mode
of the disk is equal to twice the binary orbital frequency. Under such
circumstances, the disk can be unstable to tilting and acquire a warped shape,
even in the absence of dissipation. The outer radius corresponding to the
primary resonance is always smaller than the tidal truncation radius. For disks
smaller than the primary resonance, the m=2 component may be able to cause a
very slow growth of inclination through the effect of a near resonance that
occurs close to the disk center. We discuss these results in the light of
recent observations of protostellar disks in binary systems.Comment: 21 pages, 7 figures, to be published in the Astrophysical Journa
A Wind Driven Warping Instability in Accretion Disks
A wind passing over a surface may cause an instability in the surface such as the flapping seen when wind blows across a flag or waves when wind blows across water. We show that when a radially outflowing wind blows across a dense thin rotating disk, an initially flat disk is unstable to warping. When the wind is subsonic, the growth rate is dependent on the lift generated by the wind and the phase lag between the pressure perturbation and the vertical displacement in the disk caused by drag. When the wind is supersonic, the grow rate is primarily dependent on the form drag caused by the surface. While the radiative warping instability proposed by Pringle is promising for generating warps near luminous accreting objects, we expect the wind driven instability introduced here would dominate in objects which generate energetic outflows
Assessing global resource use and greenhouse emissions to 2050, with ambitious resource efficiency and climate mitigation policies
Achieving sustainable development requires the decoupling of natural resource use and environmental pressures from economic growth and improvements in living standards. G7 leaders and others have called for improved resource efficiency, along with inclusive economic growth and deep cuts in global greenhouse emissions. However, the outlooks for and interactions between global natural resource use, resource efficiency, economic growth and greenhouse emissions are not well understood. We use a novel multi-regional modeling framework to develop projections to 2050 under existing trends and three policy scenarios. We find that resource efficiency could provide pro-growth pro-environment policies with global benefits of USD $2.4 trillion in 2050, and ease the politics of shifting towards sustainability. Under existing trends, resource extraction is projected to increase 119% from 2015 to 2050, from 84 to 184 billion tonnes per annum, while greenhouse gas emissions increase 41%, both driven by the value of global economic activity more than doubling. Resource efficiency and greenhouse abatement slow the growth of global resource extraction, so that in 2050 it is up to 28% lower than in existing trends. Resource efficiency reduces greenhouse gas emissions by 15–20% in 2050, with global emissions falling to 63% below 2015 levels when combined with a 2 °C emissions pathway. In contrast to greenhouse abatement, resource efficiency boosts near-term economic growth. These economic gains more than offset the near-term costs of shifting to a 2 °C emissions pathway, resulting in emissions in 2050 well below current levels, slower growth in resource extractions, and faster economic growth
Impacts of riverine sand mining on freshwater ecosystems: a review of the scientific evidence and guidance for future research
Sand mining (used here as a generic term that includes mining of any riverine aggregates regardless of particle size) is a global activity that is receiving increasing media attention due to perceived negative environmental and social impacts. As calls grow for stronger regulation of mining, there is a need to understand the scientific evidence to support effective management. This paper summarizes the results of a structured literature review addressing the question, “What evidence is there of impacts of sand mining on ecosystem structure, process, and biodiversity in rivers, floodplains, and estuaries?” The review found that most investigations have focused on temperate rivers where sand mining occurred historically but has now ceased. Channel incision was the most common physical impact identified; other physical responses, including habitat disturbance, alteration of riparian zones, and changes to downstream sediment transport, were highly variable and dependant on river characteristics. Ecosystem attributes affected included macroinvertebrate drift, fish movements, species abundance and community structures, and food web dynamics. Studies often inferred impacts on populations, but supporting data were scarce. Limited evidence suggests that rivers can sustain extraction if volumes are within the natural sediment load variability. Significantly, the countries and rivers for which there is science‐based evidence related to sand mining are not those where extensive sand mining is currently reported. The lack of scientific and systematic studies of sand mining in these countries prevents accurate quantification of mined volumes or the type, extent, and magnitude of any impacts. Additional research into how sand mining is affecting ecosystem services, impacting biodiversity and particularly threatened species, and how mining impacts interact with other activities or threats is urgently required
On the enigmatic X-ray Source V1408 Aql (=4U 1957+11)
Models for the characteristically soft X-ray spectrum of the compact X-ray
source V1498 Aql (=4U 1957+11) have ranged from optically thick Comptonization
to multicolor accretion disk models. We critically examine the X-ray spectrum
of V1408 Aql via archival Advanced Satellite for Cosmology and Astrophysics
(ASCA) data, archival Roentgensatellit (ROSAT) data, and recent Rossi X-Ray
Timing Explorer (RXTE) data. Although we are able to fit a variety of X-ray
spectral models to these data, we favor an interpretation of the X-ray spectrum
as being due to an accretion disk viewed at large inclination angles. Evidence
for this hypothesis includes long term (117 day, 235 day, 352 day)
periodicities seen by the RXTE All Sky Monitor (ASM), which we interpret as
being due to a warped precessing disk, and a 1 keV feature in the ASCA data,
which we interpret as being the blend of L fluorescence features from a disk
atmosphere or wind. We also present timing analysis of the RXTE data and find
upper limits of 4% for the root mean square (rms) variability between
f=0.001-16 Hz. The situation of whether the compact object is a black hole or
neutron star is still ambiguous; however, it now seems more likely that an
X-ray emitting, warped accretion disk is an important component of this system.Comment: High Frequency Power Spectrum corrected for unflagged `data dropouts'
(described in Appendix) and correct upper limits for variability presented.
All energy spectra and long term variability sections unchanged. Additional
references and acknowledgements added. 13 pages in emulateapj.st
- …