196,239 research outputs found
A CFD-based non-linear model for the prediction of tone noise in lined ducts
No full textThis paper describes the development and application of a time-domain acoustic liner model which is designed for the simulation of sound propagation and attenuation in conjunction with time-accurate unsteady flow computations using large-scale numerical models. The main duct domain is represented by the 3D Euler or Navier-Stokes equations while the resistive part of the liner model consists of a time-independent part and a non-linear time-dependent part. Its reactive part is obtained by solving the ID Euler equations within the liner cavity. A-3D-benchmark test geometry, including a lined intake, was modelled using an advanced aeroelasticity code. First, the liner model was validated for steady-state intake duct flows using a number of numerical benchmarks, with particular emphasis on the stability of the duct/liner boundary condition for a range of cases. The pressure perturbation due to the fan was investigated next via a full unsteady flow calculation. Both continuous and discontinuous liner models were considered. It was found that liner scattering had nonlinear effects on noise attenuation. It was concluded that the liner model could be used for both steady-state and unsteady flows
Proceedings of the 4th International Seminar on Non-Ideal Compressible Fluid Dynamics for Propulsion and Power. NICFD 2022 : Preface
No full textImportance of organizational culture: a model for increased engagement
No full textMeelad Sayma, Tomos Luke Treharne, Hywel Rhys WilliamsPeninsula College of Medicine and Dentistry, Plymouth, UKWe read with great interest the article by Nilsen et al,1 discussing how nursing leaders perceive their interactions and support levels from both peers and those in more senior leadership positions – in this case the municipal health director. Of particular interest was the conclusion of the paper, calling for greater coherence between different levels of leadership in the Norwegian health care setting. View original paper by Nilsen et a
The importance of public health in managing health care costs in the United Kingdom National Health Service
No full textMeelad Sayma, Tomos Luke Treharne, Hywel Rhys WilliamsPeninsula College of Medicine and Dentistry, UKMcPhail’s review tackles the problem of our generation in the developed world – the ageing population increasing the proportion of patients with multiple comorbidities.1 Combined with chronic underfunding, this problem has had, and will continue to have a huge financial burden on the United Kingdom’s National Health Service (UK NHS).2,3 In recent years, a pattern of regular crippling winter “crisis” in NHS hospitals has emerged, with some questioning the sustainability of a “free at the point of access” service.4,5 View the original paper by McPhail
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Numerical Investigation of a Wood-Chip Downdraft Gasifier
No full textBiomass gasification is regarded as one of the most promising technology in the renewable energy field. The outcome of such operation, i.e. the synfuel, can be exploited in several ways, for example powering engines and turbines, and is considered more flexible than the biomass itself. For this reason, a careful analysis of the gasification performance is of paramount importance for the optimization of the process. One of the techniques that can be used for such a purpose, is the numerical analysis. CFD is indeed a tool that can be of great help in the design and study of the operation of the gasifier, allowing for an accurate prediction of the operating parameters. In this work, a downdraft gasifier is considered, and the biomass is made of wood chip. The present analysis is devoted to build the numerical model and simulate all the reactions that happen inside an actual gasifier, considering the drying of the wood chip, heating, pyrolysis, and combustion. Good match with experimental results is found, making the numerical model here presented a reliable virtual test bench where investigating the effects of variation in the working parameters
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
A new method for teaching physical examination to junior medical students
No full textMeelad Sayma, Hywel Rhys Williams Peninsula College of Medicine and Dentistry, Plymouth, UK Introduction: Teaching effective physical examination is a key component in the education of medical students. Preclinical medical students often have insufficient clinical knowledge to apply to physical examination recall, which may hinder their learning when taught through certain understanding-based models. This pilot project aimed to develop a method to teach physical examination to preclinical medical students using “core clinical cases”, overcoming the need for “rote” learning. Methods: This project was developed utilizing three cycles of planning, action, and reflection. Thematic analysis of feedback was used to improve this model, and ensure it met student expectations. Results and discussion: A model core clinical case developed in this project is described, with gout as the basis for a “foot and ankle” examination. Key limitations and difficulties encountered on implementation of this pilot are discussed for future users, including the difficulty encountered in “content overload”. Conclusion: This approach aims to teach junior medical students physical examination through understanding, using a simulated patient environment. Robust research is now required to demonstrate efficacy and repeatability in the physical examination of other systems. Keywords: physical examination, undergraduate, case-based approach 
Design of micro-channel based actively cooled thermal shields for ultra-high temperature applications
No full textData availability:
Data will be made available on request.In this study, novel designs of high-temperature thermal shields that can be actively cooled by circulating water through a bioinspired internal microchannel network are numerically evaluated. The level of cooling that can be achieved and the thermal stresses developed in the shield material are analysed using computational fluid dynamics and finite element modelling. From the comparative analysis of those results, design guidelines for the development of such actively cooled thermal shields (ACTS) are proposed: (i) channel design plays only a minor role on the coolant mass needed to produce a desired level of cooling but (ii) small channels around the regions of maximum temperature gradient and stress concentrators like sharp corners should be avoided to prevent cracking of the shield material; and (iii) high temperature tolerance and high thermal conductivity are key parameters for the shield material. Thus, ultra-high temperature ceramics (UHTC) such as ZrB2 appear to be optimal candidates for the additive fabrication of such ACTS elements, provided they can survive the thermal cycling without cracking. Water was confirmed as an excellent coolant for such an application, enabling the development of reusable solutions for aerospace re-entry shields, involving coolant masses that could become competitive against current single-use ablative shields. Similar systems could provide suitable thermal protection or heat exchange solutions in many other demanding industrial applications.This study was carried out in the framework of the M-ERA.Net3 project AM-ACTS, grant PCI2022-132933, funded by MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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