1,068 research outputs found
Correction of non-linearity effects in detectors for electron spectroscopy
Using photoemission intensities and a detection system employed by many
groups in the electron spectroscopy community as an example, we have
quantitatively characterized and corrected detector non-linearity effects over
the full dynamic range of the system. Non-linearity effects are found to be
important whenever measuring relative peak intensities accurately is important,
even in the low-countrate regime. This includes, for example, performing
quantitative analyses for surface contaminants or sample bulk stoichiometries,
where the peak intensities involved can differ by one or two orders of
magnitude, and thus could occupy a significant portion of the detector dynamic
range. Two successful procedures for correcting non-linearity effects are
presented. The first one yields directly the detector efficiency by measuring a
flat-background reference intensity as a function of incident x-ray flux, while
the second one determines the detector response from a least-squares analysis
of broad-scan survey spectra at different incident x-ray fluxes. Although we
have used one spectrometer and detection system as an example, these
methodologies should be useful for many other cases.Comment: 13 pages, 12 figure
The servitization of manufacturing:a review of literature and reflection on future challenges
Purpose â The purpose of this paper is to report the state-of-the-art of servitization by presenting a clinical review of literature currently available on the topic. The paper aims to define the servitization concept, report on its origin, features and drivers and give examples of its adoption along with future research challenges. Design/methodology/approach â In determining the scope of this study, the focus is on articles that are central and relevant to servitization within a wider manufacturing context. The methodology consists of identifying relevant publication databases, searching these using a wide range of key words and phrases associated with servitization, and then fully reviewing each article in turn. The key findings and their implications for research are all described. Findings â Servitization is the innovation of an organisation's capabilities and processes to shift from selling products to selling integrated products and services that deliver value in use. There are a diverse range of servitization examples in the literature. These tend to emphasize the potential to maintain revenue streams and improve profitability. Practical implications â Servitization does not represent a panacea for manufactures. However, it is a concept of significant potential value, providing routes for companies to move up the value chain and exploit higher value business activities. There is little work to date that can be used to help practitioners. Originality/value â This paper provides a useful review of servitization and a platform on which to base more in-depth research into the broader topic of service-led competitive strategy by drawing on the work from other related research communities
'Heaven starts at your parents' feet' : adolescent bowing to parents and associated spiritual attitudes
In a quantitative survey of religious attitudes and practices in a multi-religious sample of
369 school pupils aged between 13 and 15 in London, the practice of bowing to parents was
found widespread in 22% of adolescents spanning several religious affiliations and
ethnicities â especially Buddhists, Hindus and those of Indian, African and âOther Asianâ
ethnicity. Whether an adolescent bowed correlated significantly with spiritual attitudes such
as wanting to abstain from alcohol, hearing religious stories, being inspired by religious
festivals and liking the idea of seeing God in everything. Findings suggest bowing to
parents can have religious significance on all three levels of Jacksonâs Interpretive
Approach and therefore cannot be regarded as a âcultural accretionâ of religion. Study of
bowing to parents could form a unifying exercise in shared values for study of religion in
the plural classroom and facilitate community cohesion in certain religious membership
groups
An exploration of policies and practices used to showcase production facilities
Manufacturers who seek innovative ways in which to differentiate their products and services should not overlook the value of showcasing their production facilities. By careful design, visitors can be exposed to a series of experiences that can help to emphasize the value built into products. This topic has, however, received almost no attention by manufacturing researchers. Therefore, this paper describes a study of six manufacturers and, from this, proposes a set of guidelines for showcasing production facilities. Although exploratory, this work provides both a guide to manufacturers and a platform for more in-depth research. The guidelines and the case studies on which they are based are all described within the paper
Regional ventilation changes in the lung: Treatment response mapping by using hyperpolarized gas MR imaging as a quantitative biomarker
Purpose: To assess the magnitude of regional response to respiratory therapeutics in the lungs using Treatment Response Mapping (TRM) with hyperpolarized gas MRI. TRM is used to quantify regional physiological response in asthmatic adults using a bronchodilator challenge.
Methods: The study was approved by the national research ethics committee and performed with informed consent. Imaging was performed in 20 adult asthmatic patients using hyperpolarized 3He ventilation MRI. Two sets of baseline images were acquired before inhalation of a bronchodilator (Inhaled Salbutamol 400 mcg) and one set was acquired after. All images were registered for voxelwise comparison. Regional treatment response, ÎR(r), is calculated as the difference in regional gas distribution (R(r) = ratio of inhaled gas to total volume of a voxel when normalized for lung inflation volume) before and after intervention. A voxelwise activation threshold from the variability of the baseline images was applied to ÎR(r) maps. The summed global TRM (ÎRnet) was then used as global lung index for comparison with metrics of bronchodilator response measured using spirometry and the global imaging metric, percentage ventilated volume (%VV).
Results: ÎRnet showed significant correlation (p<0.01) with changes in FEV1 (r=0.70), FVC (r=0.84) and %VV (r=0.56). A significant (p<0.01) positive treatment effect was detected by all metrics, however ÎRnet showed a lower inter-subject coefficient of variation (CV=64%) than all of the other tests (CVâ„99%).
Conclusions: TRM provides regional quantitative information on changes in inhaled gas ventilation in response to therapy. This method could be used as sensitive regional outcome metric of novel respiratory interventions.
Online supplemental material is available for this article
Influence of surfactants on the structure of titanium oxide gels : experiments and simulations
We report here on experimental and numerical studies of the influence of
surfactants on mineral gel synthesis. The modification of the gel structure
when the ratios water-precursor and water-surfactant vary is brought to the
fore by fractal dimension measures. A property of {\em polydispersity of the
initial hydrolysis} is proposed to explain these results, and is successfuly
tested through numerical experiments of three dimensional chemically limited
aggregation.Comment: 12 pages, 4 Postscript figures, uses RevTe
The "physical process" version of the first law and the generalized second law for charged and rotating black holes
We investigate both the ``physical process'' version of the first law and the
second law of black hole thermodynamics for charged and rotating black holes.
We begin by deriving general formulas for the first order variation in ADM mass
and angular momentum for linear perturbations off a stationary, electrovac
background in terms of the perturbed non-electromagnetic stress-energy, , and the perturbed charge current density, . Using these
formulas, we prove the "physical process version" of the first law for charged,
stationary black holes. We then investigate the generalized second law of
thermodynamics (GSL) for charged, stationary black holes for processes in which
a box containing charged matter is lowered toward the black hole and then
released (at which point the box and its contents fall into the black hole
and/or thermalize with the ``thermal atmosphere'' surrounding the black hole).
Assuming that the thermal atmosphere admits a local, thermodynamic description
with respect to observers following orbits of the horizon Killing field, and
assuming that the combined black hole/thermal atmosphere system is in a state
of maximum entropy at fixed mass, angular momentum, and charge, we show that
the total generalized entropy cannot decrease during the lowering process or in
the ``release process''. Consequently, the GSL always holds in such processes.
No entropy bounds on matter are assumed to hold in any of our arguments.Comment: 35 pages; 1 eps figur
Lodged in the throat: Internal infinities and AdS/CFT
In the context of AdS3/CFT2, we address spacetimes with a certain sort of
internal infinity as typified by the extreme BTZ black hole. The internal
infinity is a null circle lying at the end of the black hole's infinite throat.
We argue that such spacetimes may be described by a product CFT of the form
CFT-L * CFT-R, where CFT-R is associated with the asymptotically AdS boundary
while CFT-L is associated with the null circle. Our particular calculations
analyze the CFT dual of the extreme BTZ black hole in a linear toy model of
AdS3/CFT2. Since the BTZ black hole is a quotient of AdS3, the dual CFT state
is a corresponding quotient of the CFT vacuum state. This state turns out to
live in the aforementioned product CFT. We discuss this result in the context
of general issues of AdS/CFT duality and entanglement entropy.Comment: 11 pages, 2 figures; v2 - some typos corrected, minor revision
Black Hole Entropy is Noether Charge
We consider a general, classical theory of gravity in dimensions, arising
from a diffeomorphism invariant Lagrangian. In any such theory, to each vector
field, , on spacetime one can associate a local symmetry and, hence, a
Noether current -form, , and (for solutions to the field
equations) a Noether charge -form, . Assuming only that the
theory admits stationary black hole solutions with a bifurcate Killing horizon,
and that the canonical mass and angular momentum of solutions are well defined
at infinity, we show that the first law of black hole mechanics always holds
for perturbations to nearby stationary black hole solutions. The quantity
playing the role of black hole entropy in this formula is simply times
the integral over of the Noether charge -form associated with
the horizon Killing field, normalized so as to have unit surface gravity.
Furthermore, we show that this black hole entropy always is given by a local
geometrical expression on the horizon of the black hole. We thereby obtain a
natural candidate for the entropy of a dynamical black hole in a general theory
of gravity. Our results show that the validity of the ``second law" of black
hole mechanics in dynamical evolution from an initially stationary black hole
to a final stationary state is equivalent to the positivity of a total Noether
flux, and thus may be intimately related to the positive energy properties of
the theory. The relationship between the derivation of our formula for black
hole entropy and the derivation via ``Euclidean methods" also is explained.Comment: 16 pages, EFI 93-4
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