841 research outputs found
Thermodynamic assessment of the KF-ThF<sub>4</sub>, LiF-KF-ThF<sub>4</sub> and NaF-KF-ThF<sub>4</sub> systems
No full textA thermodynamic assessment of the KF-ThF4 binary system using the CALPHAD method is presented, where the liquid solution is described by the modified quasichemical formalism in the quadruplet approximation. The optimization of the phase diagram is based on experimental data reported in the literature and newly measured X-ray diffraction and differential scanning calorimetry data, which have allowed to solve discrepancies between past assessments. The low temperature heat capacity of α-K2ThF6 has also been measured using thermal relaxation calorimetry; from these data the heat capacity and standard entropy values have been derived at 298.15 K: Cp,mo(K2ThF6,cr,298.15K)=(193.2±3.9) J·K-1·mol-1 and Smo(K2ThF6,cr,298.15K)=(256.9±4.8) J·K-1·mol-1. Taking existing assessments of the relevant binaries, the new optimization is extrapolated to the ternary systems LiF-KF-ThF4 and NaF-KF-ThF4 using an asymmetric Kohler/Toop formalism. The standard enthalpy of formation and standard entropy of KNaThF6 are re-calculated from published e.m.f data, and included in the assessment of the ternary system. A calculated projection of the NaF-KF-ThF4 system at 300 K and the optimized liquidus projections of both systems are compared to published phase equilibrium data at room temperature and along the LiF-LiThF5 and NaF-KThF5 pseudobinaries, with good agreement.RST/Reactor Physics and Nuclear Material
Húsz év után. A Könyvtári Figyelő 2000–2019 között
No full textThe study provides an overview of the life of this peer-reviewed national professional journal edited at the Hungarian Library Institute in the period 2000 through 2019. Könyvtári Figyelő entered its 65th volume this year. This quarterly magazine has published 80 issues and more than 15,000 pages in PDF format in twenty years. Thanks to the support of the National Cultural Fund (NKA) printed issues continue to be published to our days. The full text of issues can be accessed and searched on an electronic interface (http://ki.oszk.hu/kf) from the beginnings (1955) to the present day (2020/1). Roughly two-thirds of each issue include research articles on the main events and developments in Hungarian librarianship, and one-third deals with the presentation of developments in the international library world. The author reviews the most important articles in the Studies, Our past, and Book reviews columns in two ten-year cycles, and refers to the professional trends summarized at the beginning of her article. The editors are increasingly oriented towards open access and the application of the Open Journal System (OJS).A tanulmány áttekintés a Könyvtári Intézetben készülő, idén 65. évfolyamába lépett, országos hatókörű, lektorált szakmai folyóirat 2000 és 2019 közötti működéséről. A negyedéves megjelenésű folyóirat húsz év alatt 80 füzetszámban, több mint 15 ezer pdf oldal terjedelemben jelent meg. Az NKA támogatásának köszönhetően ez idáig nyomtatott formában is elkészülhetett. Elektronikus felületén (http://ki.oszk.hu/kf) a kezdetektől (1955 től) napjainkig (2020/1.) elérhető és kereshető a lapszámok teljes szövege. Minden szám nagyjából kétharmadában részben a magyarországi könyvtárügy legfőbb eseményeiről és fejlesztéseiről közöl elméleti publikációkat, egyharmadában pedig a külföldi könyvtári világ fejleményeinek bemutatásával foglalkozik. Kétszer tíz éves ciklusra bontva tekinti át a szerző a Tanulmányok, a Múltunk és a Könyvszemle rovatok legfontosabb írásait, és utal a cikkek beszámolója elején felvillantott szakmai trendekkel való kapcsolatára. A szerkesztőség számára a jövő útja a nyílt hozzáférés és az Open Journal System (OJS) nyílt forráskódú szerkesztőségi rendszer kialakítása felé vezet
Payment to healthcare professionals for patient recruitment to trials: systematic review and qualitative study
No full textAim/Principal Research Question:The systematic review had three aims:• to synthesise the evidence on the effectiveness of offering monetary incentives to healthcare professionals to recruit patients to clinical trials; • to provide an overview of the ethical issues as debated in the published literature; • to identify current UK guidelines on financial incentives to healthcare professionals to recruit patients to trials.The primary research aimed to: • to identify the attitudes, beliefs and behaviour of healthcare professionals and consumers in relation to financial incentives for recruitment to trials;• to explore how financial incentives are viewed in relation to other barriers and facilitators to healthcare professionals recruiting patients to clinical trials?• to provide an overview of the current UK practice regarding the payment of financial incentives to healthcare professionals for recruitment of patients to trials.Methods:Electronic databases including the Cochrane Library, Medline, Embase, CINAHL, PsycINFO, Science Citation Index/Social Science Citation Index, Current Controlled Trials and the National Research Register were searched from inception to June 2006 for published English language studies of any payment or reimbursement to any healthcare professional recruiting patients to trials with reported recruitment rates. Bibliographies and grey literature were also searched. Inclusion criteria, data extraction and quality assessment were undertaken independently by two investigators using standard systematic review methodology. Quality assessment used the DuRant tool. Synthesis was by narrative review with full tabulation of results from all included studies. The qualitative investigation involved semi-structured interviews with purposive samples of healthcare professionals and healthcare consumers. Sampling of individuals for interview was from the National Research Register, National Coordinating Centre for Health Technology Assessment and through ‘snowballing’. Interviews were transcribed verbatim and entered into NVivo software for analysis and management. A hierarchical coding system was devised centred around themes of ‘motivation’ and ‘incentives’ for healthcare professionals, and ‘patient experiences’ and ‘incentives’ for consumers. Data is presented as representative quotations. Sample groups:Healthcare professionals and consumers, and research managers from pharmaceutical companies. Outcome measures:The primary outcome measure of the systematic review was level of patient recruitment. Secondary outcomes included other measurements of recruitment such as achievement of sample size, proportion of patients with full follow-up, qualitative measures of professional attitudes and of effects on participants. Motivating and facilitating factors and barriers to participating in research for healthcare professionals were the outcomes of the qualitative study, along with attitudes of consumers and industry research managers to incentives. Findings:Three cross-sectional surveys were identified which met the inclusion criteria. These considered recruitment rates and the attitudes and characteristics of clinicians in relation to some financial incentive or reimbursement. One primary care study reported that successful patient recruitment is determined more by motivation driven by the research group than by financial incentives, the research topic or research experience. The other primary care study concluded that patient recruitment by GPs may be aided by the use of a range of strategies including financial reimbursement, which might be enhanced by closer collaboration between GPs and researchers.The hospital based study found that reimbursement to the participating clinics was of only minor importance for both participation in trials and for recruiting patients. The scientific aims of the study were considered to be the most important factor with ethical considerations and communication between participants and researchers also of importance.In existing UK guidelines, the issues around payments to clinicians or patients are implied rather than stated, usually linked to discussion of conflict of interest and disclosure of any such conflicts. Interviews with NHS health professionals, mainly research active clinicians, indicated concerns over the likely effects of payment. While reimbursement of expenses incurred to do research was strongly supported, payment to incentivise recruitment was not. Direct payment to clinicians linked to recruitment or to research involvement was rare in publicly funded trials. A code of practice for any such payments was suggested, closely linked to the principles of Good Clinical Practice in research. Other factors such as interest in the topic, scope for patient benefit and good communication were considered more important motivations for research involvement. Interviews with the public indicated low levels of awareness of payments to clinicians linked to patient involvement in trials, and unanimous support for full disclosure of any such payments. Interviews with research managers in the pharmaceutical industry showed greater familiarity with payments for research involvement, which had in recent years shifted to payment to institutions rather than individual clinicians. GPs were the only group to whom scope existed for individual payments. Concerns were expressed by the pharmaceutical company interviewees at the rising cost of research and unnecessary bureaucracy. Conclusions:The available evidence on the effectiveness of payment to healthcare professionals for patient recruitment to trials is very limited in quality and quantity and is inconclusive. The ethical stance outlined in Good Clinical Practice in research, despite lack of scientific support, was widely endorsed. These preclude payment to patients and allow reasonable payments to clinicians, subject to disclosure of any possible conflicts of interest. Within these principles, considerable scope exists for compiling data on the factors that help and hinder the progress of clinical trials and also for experimenting with different incentives to encourage involvement in clinical research.Implications for further research:The authors recommend research on:1. Improved reporting of those organisational aspects of trials that are known to affect recruitment, including the type and extent of payments.2. Retrospective analysis of the factors associated with different levels of recruitment to RCTs, including payment of expenses to patients.3. Prospective comparative research on trial recruitment including between commercial and publicly funded trials within the NHS research networks and also between the roles of investigators and collaborators.4. Qualitative research on participants’ experiences of being involved in different kinds of trials, and also to do with the appropriateness the guidelines on payment for participation.5. Consideration by funders of clinical trails of proposals to include within trials experiments with payments methods, comparing different levels of disclosure and of payment
Thermodynamic assessment of the LiF-NiF<sub>2</sub>, NaF-NiF<sub>2</sub> and KF-NiF<sub>2</sub> systems
No full textUsing the modified quasi-chemical model in the quadruplet approximation, three new thermodynamic assessments of binary systems useful for the detailed operational design of the Molten Salt Reactor are presented: AF-NiF2 (A = Li, Na, K). These systems are particularly relevant for the study of the molten salt-structural materials interaction, as the salt containment is made of a Ni-based alloy. Using powder X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC), new experimental data were gathered for two of these systems, LiF-NiF2 and KF-NiF2, and compared to previous experimental assessments. Our data have confirmed the formation of a (Li1-2xNix)F solid solution. The three thermodynamic models show a very good agreement with the experimental data. The melting point of NiF2 was measured for the first time to be T = (1629 ± 5) K, and the thermal expansion coefficient for Li2NiF4 was found to be α=27.6·10-6K-1 in the temperature range T = (298–773) K.Accepted Author ManuscriptRST/Reactor Physics and Nuclear Material
Micro-arc oxidization of a novel Mg-1Ca alloy in three alkaline KF electrolytes: Corrosion resistance and cytotoxicity
No full textA newly-developed Mg-1Ca (wt%) alloy was treated by micro-arc oxidization (MAO) in KF-silicate- (Si coating), KF-phosphate- (P coating) and KF-silicate-phosphate (SiP coating) electrolytes. The microstructure, composition and corrosion resistance of the resultant MAO coatings were investigated using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffractometry (XRD). Electrochemical analysis and immersion test in Hanks' solution and MU assay for in-vitro toxicity against MG63 cells were subsequently carried out. Results showed that all the three MAO coatings contributed to the improvement of corrosion resistance and cytocompatibility of substrate; however, P coating outperformed the two others due to its specific microstructure and composition. (C) 2013 Elsevier B.V. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000330208500143&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, PhysicalMaterials Science, Coatings & FilmsPhysics, AppliedPhysics, Condensed MatterSCI(E)[email protected]
Chain extension reaction catalyzed by KF exo− in the presence of the modified triphosphate d(7-Ni)TP
No full text<p><b>Copyright information:</b></p><p>Taken from "Hybridization properties and enzymatic replication of oligonucleotides containing the photocleavable 7-nitroindole base analog"</p><p>Nucleic Acids Research 2005;33(5):1532-1543.</p><p>Published online 14 Mar 2005</p><p>PMCID:PMC1065254.</p><p>© The Author 2005. Published by Oxford University Press. All rights reserved</p> Experiments were investigated on different natural templates (100 nM) varying by the nature of the base N19 (N = T, sequence 13; N = C, sequence 14; N = G, sequence 15; N = A, sequence 16) hybridized to 18mer primer (sequence 12, 50 nM). In a first step, chain extension reactions were conducted in the presence of d(7-Ni)TP (1 mM) and KF exo− (0.0625 U/μl) for 5 min at 30°C (lanes 2, 6, 10 and 14). In the second step, reactions were carried out using KF exo− (0.0125 U/μl) in the presence of dATP (lanes 3, 7, 11 and 15) or in the presence of a mixture of the four dNTPs (lanes 4, 8, 12 and 16) for 20 min at 30°C
Enhanced Kalman filtering for a 2D CFD Navier-Stokes wind farm model
No full textWind turbines are often grouped together for financial reasons, but due to wake development this usually results in decreased turbine lifetimes and power capture, and thereby an increased levelized cost of energy (LCOE). Wind farm control aims to minimize this cost by operating turbines at their optimal control settings. Most state-of-the-art control algorithms are open-loop and rely on a low fidelity, static flow model. Closed-loop control relying on a dynamic model and state observer has real potential to further decrease wind's LCOE, but is often too computationally expensive for practical use. In this work two time-efficient Kalman filter (KF) variants are outlined incorporating the medium fidelity, dynamic flow model "WindFarmSimulator" (WFSim). This model relies on a discretized set of Navier-Stokes equations in 2D to predict the flow in wind farms in a horizontal plane at hub height at low computational cost. The filters implemented are an Ensemble KF and an Approximate KF. Simulations in which a high fidelity simulation model represents the true wind farm show that these filters are typically several orders of magnitude faster than a regular KF with comparable or better performance, correcting for wake dynamics that are not modeled in WFSim (noticeably, wake meandering and turbine hub effects). This is a first big step towards real-time closed-loop control in wind farms.Mechanical, Maritime and Materials EngineeringDelft Centre for Systems and Contro
Modal analysis of an operational offshore wind turbine using enhanced Kalman filter-based subspace identification
No full textOperational modal analysis (OMA) is an essential tool for understanding the structural dynamics of offshore wind turbines (OWTs). However, the classical OMA algorithms require the excitation of the structure to be stationary white noise, which is often not the case for operational OWTs due to the presence of periodic excitation caused by rotor rotation. To address this issue, several solutions have been proposed in the literature, including the Kalman filter-based stochastic subspace identification (KF-SSI) method which eliminates harmonics through estimation and orthogonal projection. In this paper, an enhanced version of the KF-SSI method is presented that involves a concatenation step, allowing multiple datasets with similar environmental conditions to be used in the identification process, resulting in higher precision. This enhanced framework is applied to an operational OWT and compared to other OMA methods, such as the modified least-squares complex exponential and PolyMAX. Using field data from a multi-megawatt operational OWT, it is shown that the enhanced framework is able to accurately distinguish the first three bending modes with more stable estimates and lower variance compared to the original KF-SSI algorithm and follows a similar trend compared to other approaches.Team Jan-Willem van Wingerde
Indoor positioning and tracking based on the received signal strength
No full textReceived Signal Strength Indicator (RSSI)-based indoor Location and Tracking (L&T) is a promising and challenging technology that enables mobile users/nodes to obtain their location information. This dissertation focuses on overcoming the challenges as well as improving the positioning accuracy for the RSSI-based L&T. In particular, the author considers 4 L&T solutions.
In the first, the author develops a L&T solution by designing the Kalman Filter (KF) to work linearly within the positioning framework. To elaborate on this implementation, the equations of the KF are presented in a consistent manner with the implementation. In the second, the author designs a L&T solution based on the Iterated Extended Kalman Filter (IEKF) to improve the accuracy compared
with the popular Extended Kalman Filter (EKF). In the third, the author overcomes the particular implementation challenges of the EKF by designing a L&T solution based on the implementation of the Scaled Unscented Transformation
(SUT) to the KF. The author calls the resulting filter Scaled Unscented Kalman Filter (SUKF). In the forth, the author overcomes the implementation difficulties of the EKF by designing a L&T solution based on the implementation of the Spherical Simplex Unscented Transformation (SSUT) to the KF. The author calls
the resulting filter the Spherical Simplex Unscented Kalman Filter (SSUKF).
The proposed solutions with their corresponding achievements enhance the role of RSSI-based L&T in wireless positioning systems. The contributions led to significant
improvement in the positioning accuracy, reliability and the ease of implementation
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