370 research outputs found
Application of Pulsed Thermography and Post-processing Techniques for CFRP Industrial Components
AbstractSeveral studies demonstrate the effectiveness of pulsed thermography for detection and visualization of sub-superficial flaws in composites. Continuous improvement of thermal data manipulation makes active thermography an attractive and powerful inspection method for industrial process control and maintenance aims. Therefore, temperature image-processing is the major ongoing challenge in the thermographic research field. However, the particular interest for thermographic inspections is to be more addressed to its simple and relatively fast industrial application; an appropriate image processing tool should be implemented and verified on industrial components, containing manufacturing and in-service defects. In the proposed research, well-established and previously proposed methods were analysed and compared for different defect typology inside three CFRP components. The main goal is not solely focused on establishing the suitable data processing approach, providing detection limits of processed data in terms of damage type, size and distribution. The aim of proposed work is to present detailed examples of thermal imaging methods applied on similar critical defects, evaluating different results among methods in terms of defects mapping capabilities and Tanimoto evaluation criterion, coupled also with the signal-to-noise ratio as assessment of defect detectability
Numerical simulation and experimental validation of fatigue behavior of wood-glass fiber composite T joint
In this paper, a numerical FE model is developed with ANSYS and validated by experimental tests to identify possible
damage locations and fatigue breakage in different wood-glass fiber composite T-joints for marine applications. Both
static and fatigue tests in three-point bending configuration have been performe
Signature for heavy Majorana neutrinos in hadronic collisions
The production and decay of new possible heavy Majorana neutrinos are
analyzed in hadronic collisions. New bounds on the mixing of these particles
with standard neutrinos are estimated according to a fundamental representation
suggested by grand unified models. A clear signature for these Majorana
neutrinos is given by same-sign dileptons plus a charged weak vector boson in
the final state. We discuss the experimental possibilities for the future Large
Hadron Collider (LHC) at CERN.Comment: Latex2e(epsfig), 12 pages, 8 figures, to appear Physical Review
Quantum Gravitational Corrections to the Real Klein-Gordon Field in the Presence of a Minimal Length
The (D+1)-dimensional -two-parameter Lorentz-covariant
deformed algebra introduced by Quesne and Tkachuk [C. Quesne and V. M. Tkachuk,
J. Phys. A: Math. Gen. \textbf {39}, 10909 (2006).], leads to a nonzero minimal
uncertainty in position (minimal length). The Klein-Gordon equation in a
(3+1)-dimensional space-time described by Quesne-Tkachuk Lorentz-covariant
deformed algebra is studied in the case where up to first order
over deformation parameter . It is shown that the modified Klein-Gordon
equation which contains fourth-order derivative of the wave function describes
two massive particles with different masses. We have shown that physically
acceptable mass states can only exist for which
leads to an isotropic minimal length in the interval . Finally, we have shown that the above estimation of
minimal length is in good agreement with the results obtained in previous
investigations.Comment: 10 pages, no figur
Adsorption Isotherms of Hydrogen: The Role of Thermal Fluctuations
It is shown that experimentally obtained isotherms of adsorption on solid
substrates may be completely reconciled with Lifshitz theory when thermal
fluctuations are taken into account. This is achieved within the framework of a
solid-on-solid model which is solved numerically. Analysis of the fluctuation
contributions observed for hydrogen adsorption onto gold substrates allows to
determine the surface tension of the free hydrogen film as a function of film
thickness. It is found to decrease sharply for film thicknesses below seven
atomic layers.Comment: RevTeX manuscript (3 pages output), 3 figure
Signatures of heavy Majorana neutrinos and HERA's isolated lepton events
The graph of neutrinoless double beta decay is applied to HERA and
generalized to final states with any two charged leptons. Considered is the
case in which one of the two escapes typical identification criteria and the
case when a produced tau decays hadronically. Both possibilities give one
isolated lepton with high transverse momentum, hadronic activity and an
imbalance in transverse momentum. We examine the kinematical properties of
these events and compare them with the high p_T isolated leptons reported by
the H1 collaboration. Their positive charged muon events can be explained by
the ``double beta'' process and we discuss possibilities for the precise
determination which original final state produced the single isolated lepton.
To confirm our hypothesis one should search in the data for high pseudorapidity
and/or low p_T leptons or for additional separated jets.Comment: 19 pages with 14 figures, minor change
Seesaw Neutrino Signals at the Large Hadron Collider
We discuss the scenario with gauge singlet fermions (right-handed neutrinos)
accessible at the energy of the Large Hadron Collider. The singlet fermions
generate tiny neutrino masses via the seesaw mechanism and also have sizable
couplings to the standard-model particles. We demonstrate that these two facts,
which are naively not satisfied simultaneously, are reconciled in the
five-dimensional framework in various fashions, which make the seesaw mechanism
observable. The collider signal of tri-lepton final states with transverse
missing energy is investigated for two explicit examples of the observable
seesaw, taking account of three types of neutrino mass spectrum and the
constraint from lepton flavor violation. We find by showing the significance of
signal discovery that the collider experiment has a potential to find signals
of extra dimensions and the origin of small neutrino masses.Comment: 27 pages, 4 figure
Grand unified theory constrained supersymmetry and neutrinoless double beta decay
We analyze the contributions to the neutrinoless double decay
(-decay) coming from the Grand Unified Theory (GUT) constrained
Minimal Supersymmetric Standard Model (MSSM) with trilinear R-parity breaking.
We discuss the importance of two-nucleon and pion-exchange realizations of the
quark-level -decay transitions. In this context, the questions
of reliability of the calculated relevant nuclear matrix elements within the
Renormalized Quasiparticle Random Phase Approximation (pn-RQRPA) for several
medium and heavy open-shell nuclei are addressed. The importance of gluino and
neutralino contributions to -decay is also analyzed. We review
the present experiments and deduce limits on the trilinear R-parity breaking
parameter from the non-observability of -decay
for different GUT constrained SUSY scenarios. In addition, a detailed study of
limits on the MSSM parameter space coming from the processes
by using the recent CLEO and OPAL results is performed. Some studies in respect
to the future -decay project GENIUS are also presented.Comment: 29 pages, 8 figure
Pair production of the heavy leptons in future high energy linear e^{+}e^{-} colliders
The littlest Higgs model with T-parity predicts the existence of the T-odd
particles, which can only be produced in pair. We consider pair production of
the T-odd leptons in future high energy linear collider ().
Our numerical results show that, as long as the T-odd leptons are not too
heavy, they can be copiously produced and their possible signals might be
detected via the processes in future
experiments.Comment: Discussions added, typos and references correcte
Effects of clinical pathways in the joint replacement: a meta-analysis
<p>Abstract</p> <p>Background</p> <p>A meta-analysis was performed to evaluate the use of clinical pathways for hip and knee joint replacements when compared with standard medical care. The impact of clinical pathways was evaluated assessing the major outcomes of in-hospital hip and knee joint replacement processes: postoperative complications, number of patients discharged at home, length of in-hospital stay and direct costs.</p> <p>Methods</p> <p>Medline, Cinahl, Embase and the Cochrane Central Register of Controlled Trials were searched. The search was performed from 1975 to 2007. Each study was assessed independently by two reviewers. The assessment of methodological quality of the included studies was based on the Jadad methodological approach and on the New Castle Ottawa Scale. Data analysis abided by the guidelines set out by The Cochrane Collaboration regarding statistical methods. Meta-analyses were performed using RevMan software, version 4.2.</p> <p>Results</p> <p>Twenty-two studies met the study inclusion criteria and were included in the meta-analysis for a total sample of 6,316 patients. The aggregate overall results showed significantly fewer patients suffering postoperative complications in the clinical pathways group when compared with the standard care group. A shorter length of stay in the clinical pathway group was also observed and lower costs during hospital stay were associated with the use of the clinical pathways. No significant differences were found in the rates of discharge to home.</p> <p>Conclusion</p> <p>The results of this meta-analysis show that clinical pathways can significantly improve the quality of care even if it is not possible to conclude that the implementation of clinical pathways is a cost-effective process, because none of the included studies analysed the cost of the development and implementation of the pathways. Based on the results we assume that pathways have impact on the organisation of care if the care process is structured in a standardised way, teams critically analyse the actual organisation of the process and the multidisciplinary team is highly involved in the re-organisation. Further studies should focus on the evaluation of pathways as complex interventions to help to understand which mechanisms within the clinical pathways can really improve the quality of care. With the need for knee and hip joint replacement on the rise, the use of clinical pathways might contribute to better quality of care and cost-effectiveness.</p
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