30,919 research outputs found
Thermal comfort guidelines for production spaces within multi-storey garment factories located in Bangladesh
This research presents extensive field data on indoor thermal conditions along with workers' comfort votes taken at their workstations within three existing multi-storied garment factories during the three seasons (cool-dry, hot-dry and warm-humid) of Bangladesh. The main objective of the study was to observe the impact of thermal conditions on workers’ indoor thermal perception during each season of a year and from this identify thermal comfort guidelines (e.g. neutral temperatures, comfort ranges, preferred airspeeds and directions) to execute their production work comfortably. Subjective votes were collected from a total of 908 workers with the thermal data, physiological data and adaptive measures recorded simultaneously. Statistical analyses revealed that workers can accept a wider and relatively higher comfort range than the predicted band during cool-dry and hot-dry seasons, for instance, 22.7–29.1 °C and 22.3–30.4 °C respectively. A narrower comfort band (e.g. 28.7–30.9 °C), close to the predicted range, was found during the warm-humid season, which can be maintained by reducing radiant temperature and elevating airspeed. Further analyses indicated that workers prefer a mean airspeed of 0.3 m/s and comfort range of 0–3.0 m/s specific to their activities preferably from inlets located on south, north and east facades while upward and downward air movement, from for example ceiling fans, causes a rise of air temperature in the occupational zone and thermal discomfort. This research also suggested that the maximum distances of workstations from the ventilation inlets (windows) should be maintained at 12–18 m for sufficient cross ventilation, personal controls and adaptive opportunities to help maintain preferred thermal condition
Exploring the challenges of implementing e-health: a protocol for an update of a systematic review of reviews.
There is great potential for e-health to deliver cost-effective, quality healthcare and spending on e-health systems by governments and healthcare systems is increasing worldwide. However, the literature often describes problematic and unsuccessful attempts to implement these new technologies into routine clinical practice. To understand and address the challenges of implementing e-health, a systematic review was conducted in 2009, which identified several conceptual barriers and facilitators to implementation. As technology is rapidly changing and new e-health solutions are constantly evolving to meet the needs of current practice, an update of this review is deemed necessary to understand current challenges to the implementation of e-health. This research aims to identify, summarise and synthesise currently available evidence, by undertaking a systematic review of reviews to explore the barriers and facilitators to implementing e-health across a range of healthcare settings
Action and Energy of the Gravitational Field
We present a detailed examination of the variational principle for metric
general relativity as applied to a ``quasilocal'' spacetime region \M (that
is, a region that is both spatially and temporally bounded). Our analysis
relies on the Hamiltonian formulation of general relativity, and thereby
assumes a foliation of \M into spacelike hypersurfaces . We allow for
near complete generality in the choice of foliation. Using a field--theoretic
generalization of Hamilton--Jacobi theory, we define the quasilocal
stress-energy-momentum of the gravitational field by varying the action with
respect to the metric on the boundary \partial\M. The gravitational
stress-energy-momentum is defined for a two--surface spanned by a spacelike
hypersurface in spacetime. We examine the behavior of the gravitational
stress-energy-momentum under boosts of the spanning hypersurface. The boost
relations are derived from the geometrical and invariance properties of the
gravitational action and Hamiltonian. Finally, we present several new examples
of quasilocal energy--momentum, including a novel discussion of quasilocal
energy--momentum in the large-sphere limit towards spatial infinity.Comment: To be published in Annals of Physics. This final version includes two
new sections, one giving examples of quasilocal energy and the other
containing a discussion of energy at spatial infinity. References have been
added to papers by Bose and Dadhich, Anco and Tun
Carbon Rich Extremely Metal Poor Stars: Signatures of Population-III AGB stars in Binary Systems
We use the Cambridge stellar evolution code STARS to model the evolution and
nucleosynthesis of zero-metallicity intermediate-mass stars. We investigate the
effect of duplicity on the nucleosynthesis output of these systems and the
potential abundances of the secondaries. The surfaces of zero-metallicity stars
are enriched in CNO elements after second dredge up. During binary interaction,
such as Roche lobe overflow or wind accretion, metals can be released from
these stars and the secondaries enriched in CNO isotopes. We investigate the
formation of the two most metal poor stars known, HE 0107-5240 and HE
1327-2326. The observed carbon and nitrogen abundances of HE 0107-5240 can be
reproduced by accretion of material from the companion-enhanced wind of a seven
solar star after second dredge-up, though oxygen and sodium are underproduced.
We speculate that HE 1327-2326, which is richer in nitrogen and strontium, may
similarly be formed by wind accretion in a later AGB phase after third
dredge-up.Comment: 16 pages, 1 figure, 7 tables, accepted by MNRA
IMEX evolution of scalar fields on curved backgrounds
Inspiral of binary black holes occurs over a time-scale of many orbits, far
longer than the dynamical time-scale of the individual black holes. Explicit
evolutions of a binary system therefore require excessively many time steps to
capture interesting dynamics. We present a strategy to overcome the
Courant-Friedrichs-Lewy condition in such evolutions, one relying on modern
implicit-explicit ODE solvers and multidomain spectral methods for elliptic
equations. Our analysis considers the model problem of a forced scalar field
propagating on a generic curved background. Nevertheless, we encounter and
address a number of issues pertinent to the binary black hole problem in full
general relativity. Specializing to the Schwarzschild geometry in Kerr-Schild
coordinates, we document the results of several numerical experiments testing
our strategy.Comment: 28 pages, uses revtex4. Revised in response to referee's report. One
numerical experiment added which incorporates perturbed initial data and
adaptive time-steppin
Toxic level hypergolic vapor detection sensor development
Development of an electrochemical sensor technology capable of PPB level hypergolic vapor sensing is reported. A portable instrument capable of meeting the design goals is described
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