723 research outputs found
A Partial Taxonomy of Substitutability and Interchangeability
Substitutability, interchangeability and related concepts in Constraint
Programming were introduced approximately twenty years ago and have given rise
to considerable subsequent research. We survey this work, classify, and relate
the different concepts, and indicate directions for future work, in particular
with respect to making connections with research into symmetry breaking. This
paper is a condensed version of a larger work in progress.Comment: 18 pages, The 10th International Workshop on Symmetry in Constraint
Satisfaction Problems (SymCon'10
Flared landing approach flying qualities. Volume 2: Appendices
An in-flight research study was conducted utilizing the USAF/Total In-Flight Simulator (TIFS) to investigate longitudinal flying qualities for the flared landing approach phase of flight. A consistent set of data were generated for: determining what kind of command response the pilot prefers/requires in order to flare and land an aircraft with precision, and refining a time history criterion that took into account all the necessary variables and the characteristics that would accurately predict flying qualities. Seven evaluation pilots participated representing NASA Langley, NASA Dryden, Calspan, Boeing, Lockheed, and DFVLR (Braunschweig, Germany). The results of the first part of the study provide guidelines to the flight control system designer, using MIL-F-8785-(C) as a guide, that yield the dynamic behavior pilots prefer in flared landings. The results of the second part provide the flying qualities engineer with a derived flying qualities predictive tool which appears to be highly accurate. This time-domain predictive flying qualities criterion was applied to the flight data as well as six previous flying qualities studies, and the results indicate that the criterion predicted the flying qualities level 81% of the time and the Cooper-Harper pilot rating, within + or - 1%, 60% of the time
Flared landing approach flying qualities. Volume 1: Experiment design and analysis
An inflight research study was conducted utilizing the USAF Total Inflight Simulator (TIFS) to investigate longitudinal flying qualities for the flared landing approach phase of flight. The purpose of the experiment was to generate a consistent set of data for: (1) determining what kind of commanded response the pilot prefers in order to flare and land an airplane with precision, and (2) refining a time history criterion that took into account all the necessary variables and their characteristics that would accurately predict flying qualities. The result of the first part provides guidelines to the flight control system designer, using MIL-F-8785-(C) as a guide, that yield the dynamic behavior pilots perfer in flared landings. The results of the second part provides the flying qualities engineer with a newly derived flying qualities predictive tool which appears to be highly accurate. This time domain predictive flying qualities criterion was applied to the flight data as well as six previous flying qualities studies, and the results indicate that the criterion predicted the flying qualities level 81% of the time and the Cooper-Harper pilot rating, within + or - 1, 60% of the time
Renal Function in Relation to Cardiac 123I-MIBG Scintigraphy in Patients with Chronic Heart Failure
The aim of this study was to explore if estimates of renal function could
explain variability of 123I-metaiodobenzylguanidine (123I-MIBG) assessed myocardial sympathetic activity. Furthermore estimates of renal function were compared to 123I-MIBG as predictors of cardiac death in chronic heart failure (CHF). Semi-quantitative parameters of 123I-MIBG myocardial uptake and washout were calculated using early heart/mediastinum ratio (H/M), late H/M and washout. Renal function was calculated as estimated Creatinine Clearance (e-CC) and as estimated Glomerular Filtration Rate (e-GFR). Thirty-nine patients with CHF (24 males; age: 64.4 ± 10.5 years; NYHA II/III/IV: 17/20/2; LVEF: 24.0 ± 11.5%) were studied. Variability in any of the semi-quantitative 123I-MIBG myocardial parameters could not be explained by e-CC or e-GFR. During follow-up (60 ± 37 months) there were 6 cardiac deaths. Cox proportional hazard regression analysis showed that late H/M was the only independent predictor for cardiac death (Chi-square 3.2, regression coefficient: −4.095; standard error: 2.063; hazard ratio: 0.17 [95% CI: 0.000–0.950]). Addition of estimates of renal function did not significantly change the Chi-square of the model. Semi-quantitative 123I-MIBG myocardial parameters are independent of estimates of renal function. In addition, cardiac sympathetic innervation assessed by 123I-MIBG scintigraphy seems to be superior to renal function in the prediction of cardiac death in CHF patients
Original biographies from the Dictionary of African Christian Biography
A publication of the Dictionary of African Christian Biography with U.S. offices located at the Center for Global Christianity and Mission at Boston University. The editors are pleased to offer the first annual cumulative volume of the Journal of African Christian Biography, the monthly scholarly publication that was launched in June of 2016. Since then, the life stories of twelve individuals who played vital roles in and through their faith communities have been published online as free downloads. But it is important that a selection of DACB stories be more readily available to those without access to the internet. As I mentioned in the fall 2016 newsletter of the DACB, each issue of the journal is available in its e-journal, on-line version, where it is configured either as A4 or 8.5 x 11 format printable as booklets, ready for local printing and binding or stapling. Our intention is to make it easy for academics and church leaders in various parts of Africa to make print copies of the journal available to their students, colleagues or church members. And so it is with this cumulative volume.This issue focuses on: 1. "Walatta Petros and Hakalla Amale, Pious Women of Ethiopia," with commentary by Dr. Jonathan Bonk, Project Director. 2. Walatta Petros. 3. Hakalla Amale. 4. Bishop Josiah Kibira of Tanzania, Ecumenical Statesman. 5. Josiah Mutabuzi Isaya Kibira. 6. Josiah Kibira. 7. David Lonkibiri Windibiziri. 8. Abiodun Babatunde Lawrence. 9. Dominic Ignatius Ekandem. 10. William Wadé Harris, Prophet-Evangelist of West Africa: His Life, Message, Praxis, Heritage, and Legacy. 11. William Wadé Harris. 12. Michael Timneng and Jeremiah Chi Kangsen: Christianity Beyond the Missionary Presence in Cameroon. 13. Michael Timneng. 14. Jeremiah Chi Kangsen. 15. Rainisoalambo, Ravelonjanahary, and Volahavana Germaine (Nenilava): Revival Leaders of Madagascar. 16. Rainisoalambo. 17. Ravelonjanahary. 18. Volahavana Germaine (Nenilava). 19. Recent Print and Digital Resourcews Related to Christianity in Africa
Investigating Ramp Wave Propagation inside Silica Glass with Laser Experiments and Molecular Simulations
Under elastic shock compression silica glass exhibits a very specific behaviour. A shock propagating inside a material is usually seen as the propagation of a discontinuity. However in silica glass, shocks are unstable and lead to the propagation of a ramp wave where the shock front becomes gradually larger over time. Ramp waves were already reported in the literature, however their origin remain uncertain. This work presents an original study combining laser shock-induced experiments and molecular dynamics simulation aiming to improve the understanding of the mechanisms involved. Experimental ramp waves were directly observed using shadowgraphy technique allowing for an estimation of the head and tail velocities. Molecular dynamics simulations were carried out in order to reproduce ramp waves and to gain insight into the material properties. Ramp waves were observed for both elastic and plastic shockwaves. In the latter case, the plastic waves were preceded by an elastic ramp precursor. The sound speed, related to the material compressibility, was found to decrease with increasing pressure, as observed experimentally for quasi-static hydrostatic loading, thus providing an explanation for the instabilities that lead to the propagation of ramp waves
Etude par choc laser de l'adhérence de barrières thermiques aéronautiques
National audienceL'estimation de la durée de vie des barrières thermiques aéronautiques (BT) déposées sur les aubes de turbines haute pression nécessite de comprendre les mécanismes induisant l'endommagement entre la sous-couche et la zircone. Le LASAT, LAser Shock Adhesion Test ou essai d'adhérence par choc laser, est une technique exploitant tout son potentiel dans le cas des BTs, en particulier par sa rapidité, simplicité et au comportement optique de la couche de zircone. Ce dernier avantage permet de dimensionner l'endommagement généré sans réaliser de coupes métallographiques. Un nouveau protocole de l'essai LASAT a été mis en place utilisant les ondes de choc bidimensionnelles et exploitant la dépendance entre l'intensité du choc appliqué, le niveau d'adhérence du dépôt, et la dimension de la fissure générée
Laser Shock Adhesion Test (LASAT) of electron beam physical vapor deposited thermal barrier coatings (EB-PVD TBCs)
International audienceDamage prediction, adhesion strength and remaining lifetime of TBC are highly important data for understanding and preventing TBC spallation on blades. LAser Shock Adhesion Test (LASAT) is a powerful method to measure adhesion of coating due to its rapidity, simplicity and capabilities to distinguish different strength levels and the easy damage observation in case of TBCs. A new protocol of LASAT has been introduced in order to measure the adhesion level of the ceramic coating from the exploitation of the two-dimensional effects that promotes a shock wave pressure-dependent size of the damage. Finite element modeling, taking into account the TBCs dimensions, showed the edges effect on interfacial stress applied by laser shock
The determinants of sustained adherence to COVID-19 preventive measures among older Syrian refugees in Lebanon
Acknowledgments The authors thank the participants at the Economic Research Forum annual conference in March 2022 for comments. Funding: SA and HG received the ELRHA Research for Health in Humanitarian Crises award (Number 51538) for "Tracking adherence of older refugees to COVID-19 preventive measures in response to changing vulnerabilities: A multi-level, panel study to inform humanitarian response in Lebanon". This work was supported by ELRHA’s Research for Health in Humanitarian Crisis (R2HC) Programme, which aims to improve health outcomes by strengthening the evidence base for public health interventions in humanitarian crises. R2HC is funded by the UK Foreign, Commonwealth and Development Office (FCDO), Wellcome, and the UK National Institute for Health Research (NIHR). The views expressed herein should not be taken, in any way, to reflect the official opinion of the NRC or ELRHA. The funding agency was not involved in the data collection, analysis or interpretation. ELRHA: https://www.elrha.org/programme/research-for-health-in-humanitarian-crises/ The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.Peer reviewedPublisher PD
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