scholarly journals Making the Most of Parameter Estimation: Terpolymerization Troubleshooting Tips

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 444 ◽  
Author(s):  
Scott ◽  
Gabriel ◽  
Dubé ◽  
Penlidis
Keyword(s):  
Parameter Estimation ◽  
Case Studies ◽  
Ternary Systems ◽  
Reactivity Ratio ◽  
Prediction Performance ◽  
Reactivity Ratios ◽  
Ratio Estimation ◽  
New Material ◽  
Future Work ◽  
Good Agreement

Multi-component polymers can provide many advantages over their homopolymer counterparts. Terpolymers are formed from the combination of three unique monomers, thus creating a new material that will exhibit desirable properties based on all three of the original comonomers. To ensure that all three comonomers are incorporated (and to understand and/or predict the degree of incorporation of each comonomer), accurate reactivity ratios are vital. In this study, five terpolymerization studies from the literature are revisited and the ‘ternary’ reactivity ratios are re-estimated. Some recent studies have shown that binary reactivity ratios (that is, from the related copolymer systems) do not always apply to ternary systems. In other reports, binary reactivity ratios are in good agreement with terpolymer data. This investigation allows for the comparison between previously determined binary reactivity ratios and newly estimated ‘ternary’ reactivity ratios for several systems. In some of the case studies presented herein, reactivity ratio estimation directly from terpolymerization data is limited by composition restrictions or ill-conditioned systems. In other cases, we observe similar or improved prediction performance (for ternary systems) when ‘ternary’ reactivity ratios are estimated directly from terpolymerization data (compared to the traditionally used binary reactivity ratios). In order to demonstrate the advantages and challenges associated with ‘ternary’ reactivity ratio estimation, five case studies are presented (with examples and counter-examples) and troubleshooting suggestions are provided to inform future work.

New strength metrics for containerboards: influences of basic papermaking factors

2018 ◽  
Vol 33 (4) ◽  
pp. 592-602
Author(s):  
Amanda Mattsson ◽  
Tetsu Uesaka
Keyword(s):  
Time Dependent ◽  
New Method ◽  
Creep Tests ◽  
Material Parameters ◽  
Dependent Failures ◽  
Short Term Strength ◽  
New Material ◽  
End Use ◽  
Future Work ◽  
Operating Window

Abstract In end-use, containerboard is subjected to a variety of loading histories, such as seconds of loading/unloading, hours of vibration, days of creep load. The fundamental question is whether the commonly measured static strength represents “strength” under these conditions. Another question is, since those time-dependent failures are notoriously variable, how to describe the probabilistic aspect. This study concerns the characterisation of these different facets of “strength”. In our earlier work, we have investigated the theoretical framework for time-dependent, probabilistic failures, and identified three material parameters: (1) characteristic strength, {S_{c}}, representing short-term strength, (2) brittleness/durability parameter, ρ, and (3) reliability parameter, β. We have also developed a new method that allows us to determine all these parameters much faster than typical creep tests. Using the new method, we have started investigating effects of basic papermaking variables on the new material parameters. Among the samples tested, the parameter ρ varied from 20 to 50, and β from 0.5 to 1.0. This suggests that, even within the current papermaking practice, there is a wide operating window to tune these new material parameters. The future work is, therefore, to find specific manufacturing variables that can systematically change these new material parameters.

Monomer Reactivity Ratios and Chain Segment Distribution for AM/2-EHA Copolymer

2015 ◽  
Vol 1083 ◽  
pp. 9-14
Author(s):  
Ming Tian ◽  
Yong Jun Xu
Keyword(s):  
Reactivity Ratio ◽  
Control Agent ◽  
Copolymer Composition ◽  
Reactivity Ratios ◽  
Chain Segment ◽  
Element Analysis ◽  
Free Radical Copolymerization ◽  
Copolymer Chain ◽  
Profile Control ◽  
Segment Distribution

A new copolymer of acrylamide (AM) and Isobutane-Ethylhexyl acrylate (2-EHA) was synthesized as profile control agent by free radical copolymerization. The copolymer composition obtained by element analysis method led to determination of reactivity ratio by employing YBR calculative method. The result indicated that the reactivity ratios of AM and 2-EHA were 0.856and 0.592 respectively. The chain segment distribution of copolymer was investigated from reactivity ratio and the microstructure of copolymer molecule was analyzed. The results showed that the ratios in feed can hardly change the chain segment distribution. The proportion of 1M1 decreased with the increase of AM in feed. AM and 2-EHA had a tendency to alternate in copolymer chain when f1=0.286~0.375. The monomer which had a low ratio in feed inserted in copolymer chain with 1M chain segment and the other monomer was separated evenly. It can help to study copolymerization for AM and 2-EHA for industrial production in mass.

scholarly journals Electronic health records in ambulances: the ERA multiple-methods study

2020 ◽  
Vol 8 (10) ◽  
pp. 1-140
Author(s):  
Alison Porter ◽  
Anisha Badshah ◽  
Sarah Black ◽  
David Fitzpatrick ◽  
Robert Harris-Mayes ◽  
...  
Keyword(s):  
Emergency Department ◽  
Health Services ◽  
Electronic Health Records ◽  
Case Studies ◽  
Routine Data ◽  
Health Economy ◽  
Multiple Methods ◽  
Health Records ◽  
Electronic Health ◽  
Future Work

Background Ambulance services have a vital role in the shift towards the delivery of health care outside hospitals, when this is better for patients, by offering alternatives to transfer to the emergency department. The introduction of information technology in ambulance services to electronically capture, interpret, store and transfer patient data can support out-of-hospital care. Objective We aimed to understand how electronic health records can be most effectively implemented in a pre-hospital context in order to support a safe and effective shift from acute to community-based care, and how their potential benefits can be maximised. Design and setting We carried out a study using multiple methods and with four work packages: (1) a rapid literature review; (2) a telephone survey of all 13 freestanding UK ambulance services; (3) detailed case studies examining electronic health record use through qualitative methods and analysis of routine data in four selected sites consisting of UK ambulance services and their associated health economies; and (4) a knowledge-sharing workshop. Results We found limited literature on electronic health records. Only half of the UK ambulance services had electronic health records in use at the time of data collection, with considerable variation in hardware and software and some reversion to use of paper records as services transitioned between systems. The case studies found that the ambulance services’ electronic health records were in a state of change. Not all patient contacts resulted in the generation of electronic health records. Ambulance clinicians were dealing with partial or unclear information, which may not fit comfortably with the electronic health records. Ambulance clinicians continued to use indirect data input approaches (such as first writing on a glove) even when using electronic health records. The primary function of electronic health records in all services seemed to be as a store for patient data. There was, as yet, limited evidence of electronic health records’ full potential being realised to transfer information, support decision-making or change patient care. Limitations Limitations included the difficulty of obtaining sets of matching routine data for analysis, difficulties of attributing any change in practice to electronic health records within a complex system and the rapidly changing environment, which means that some of our observations may no longer reflect reality. Conclusions Realising all the benefits of electronic health records requires engagement with other parts of the local health economy and dealing with variations between providers and the challenges of interoperability. Clinicians and data managers, and those working in different parts of the health economy, are likely to want very different things from a data set and need to be presented with only the information that they need. Future work There is scope for future work analysing ambulance service routine data sets, qualitative work to examine transfer of information at the emergency department and patients’ perspectives on record-keeping, and to develop and evaluate feedback to clinicians based on patient records. Study registration This study is registered as Health and Care Research Wales Clinical Research Portfolio 34166. Funding This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 10. See the NIHR Journals Library website for further project information.

scholarly journals Characterization of the unsteady aerodynamic response of a floating offshore wind turbine

2020 ◽  
Author(s):  
Simone Mancini ◽  
Koen Boorsma ◽  
Marco Caboni ◽  
Marion Cormier ◽  
Thorsten Lutz ◽  
...  
Keyword(s):  
Numerical Models ◽  
Aerodynamic Performance ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
High Fidelity ◽  
Aerodynamic Damping ◽  
Unsteady Aerodynamic ◽  
Future Work ◽  
Good Agreement

Abstract. The disruptive potential of floating wind turbines has attracted the interest of both industry and scientific community. Lacking a rigid foundation, such machines are subject to large displacements whose impact on the aerodynamic performance is not yet fully acknowledged. In this work, the unsteady aerodynamic response to an harmonic surge motion of a scaled version of the DTU10MW turbine is investigated in detail. The imposed displacements have been chosen representative of typical platform motions. The results of different numerical models are validated against high fidelity wind tunnel tests specifically focused on the aerodynamics. Also a linear analytical model, relying on the quasi-steady assumption, is presented as a theoretical reference. The unsteady responses are shown to be dominated by the first surge harmonic and a frequency domain characterization, mostly focused on the thrust oscillation, is conducted involving aerodynamic damping and mass parameters. A very good agreement among codes, experiments and quasi-steady theory has been found clarifying some literature doubts. A convenient way to describe the unsteady results in non-dimensional form is proposed, hopefully serving as reference for future work.

scholarly journals Solution copolymerization of ethylene and propylene by salicylaldiminato-derived [O-NS]TiCl3/MAO catalysts: synthesis, characterization and reactivity ratio estimation

RSC Advances ◽  
2017 ◽  
Vol 7 (17) ◽  
pp. 10175-10182
Author(s):  
Zhen Yao ◽  
Da-Feng Ma ◽  
Zhi-xian Xiao ◽  
Wen-long Yang ◽  
Yu-Xia Tu ◽  
...  
Keyword(s):  
Reactivity Ratio ◽  
Toluene Solution ◽  
Ratio Estimation ◽  
Co Catalyst

Salicylaldiminato-derived [O-NS]TiCl3 is used in the copolymerization of ethylene and propylene in toluene solution with methylaluminoxane as the co-catalyst.

scholarly journals Watching over or Working with? Understanding Social Work Innovation in Response to Extra-Familial Harm

2020 ◽  
Vol 9 (4) ◽  
pp. 37 ◽  
Author(s):  
Lauren Elizabeth Wroe ◽  
Jenny Lloyd
Keyword(s):  
Social Work ◽  
Case Studies ◽  
Analytical Framework ◽  
Analytic Framework ◽  
England And Wales ◽  
Critical Issues ◽  
And Control ◽  
Future Work ◽  
Public Bodies

This paper critically reflects on the role of surveillance and trusted relationships in social work in England and Wales. It explores the characteristics of relationships of trust and relationships of surveillance and asks how these approaches apply to emerging policy and practices responses to extra-familial forms of harm (EFH). Five bodies of research that explore safeguarding responses across a range of public bodies are drawn on to present an analytical framework that explores elements of safeguarding responses, constituting relationships of trust or relationships of surveillance and control. This analytic framework is applied to two case studies, each of which detail a recent practice innovation in response to EFH studied by the authors, as part of a larger body of work under the Contextual Safeguarding programme. The application of this framework signals a number of critical issues related to the focus/rationale, methods and impact of interventions into EFH that should be considered in future work to address EFH, to ensure young people’s rights to privacy and participation are upheld.

Superplastic Materials Characterisation Based on Free-Bulge Tests

2020 ◽  
Vol 306 ◽  
pp. 15-22
Author(s):  
Luis García-Barrachina ◽  
A.J. Gámez
Keyword(s):  
Parameter Estimation ◽  
Tensile Test ◽  
Apparent Viscosity ◽  
Experimental Tests ◽  
Characteristic Parameters ◽  
Forming Process ◽  
Viscosity Function ◽  
Computer Aided ◽  
Fluid Behaviour ◽  
Good Agreement

A new characterisation method based on free-bulge tests is proposed to find the characteristic parameters of the strainstress relation in superplastic alloys. The method is applied to experimental tests found in the literature and to new adhoc tests performed on aluminium, magnesium and titanium alloys. The parameters are then compared to independent values obtained from tensile test and computer-aided simulations. The characterisation of the material is evaluated as an apparent viscosity function of the strain-rate and is extracted from the height evolution at the apex dome during the forming process. Results show a good agreement between parameter estimation using this method and independent values. Moreover, this characterisation method exposes the non-newtonian fluid behaviour of these materials during superplastic processes known as shear-thinning or pseudoplasticity.

Numerical Simulation of the Charging of Liquid Storage Tanks: Comparison With Experiment

1989 ◽  
Vol 111 (3) ◽  
pp. 225-231 ◽  
Author(s):  
M. F. Lightstone ◽  
G. D. Raithby ◽  
K. G. T. Hollands
Keyword(s):  
Plug Flow ◽  
Energy System ◽  
Hot Water ◽  
Storage Tanks ◽  
Fluid Turbulence ◽  
Liquid Storage ◽  
Model Predictions ◽  
Future Work ◽  
Insight Into ◽  
Good Agreement

The degree of thermal stratification maintained in hot water storage tanks has a significant impact on the performance of a solar energy system. This paper presents an axisymmetric finite volume model analysis of the charging of a tank with hot water, and compares the predictions with experimental results from the literature. The results show the capabilities and deficiencies of such a modeling technique for this type of problem. The importance of inlet fluid turbulence to tank destratification is demonstrated and inclusion of a simple turbulence model is found sufficient to yield good agreement with measurement. The model predictions also provide insight into when a simple one-dimensional plug flow model will be adequate. In addition, the model is used to evaluate the effect during charging of heat conduction in the tank wall on the temperature field in the fluid. Recommendations are made regarding future work on the development of detailed numerical codes for simulating the charging of liquid storage tanks.

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